U.S. patent application number 12/754800 was filed with the patent office on 2010-10-14 for serotonin and norepinephrine reuptake inhibitor.
This patent application is currently assigned to Eli Lilly and Company. Invention is credited to Nicolas Jacques Francois DREYFUS, Sandra Ann FILLA, Anette Margareta JOHANSSON, Thierry J. MASQUELIN, Jikesh Arvind SHAH, Eric George TROMICZAK, Magnus Wilhelm WALTER.
Application Number | 20100261762 12/754800 |
Document ID | / |
Family ID | 42698378 |
Filed Date | 2010-10-14 |
United States Patent
Application |
20100261762 |
Kind Code |
A1 |
DREYFUS; Nicolas Jacques Francois ;
et al. |
October 14, 2010 |
SEROTONIN AND NOREPINEPHRINE REUPTAKE INHIBITOR
Abstract
A serotonin and norepinephrine reuptake inhibitor of the
formula: ##STR00001## its uses, and methods for its preparation are
described.
Inventors: |
DREYFUS; Nicolas Jacques
Francois; (Basingstoke, GB) ; FILLA; Sandra Ann;
(Franklin, IN) ; JOHANSSON; Anette Margareta;
(Indianapolis, IN) ; MASQUELIN; Thierry J.;
(Westfield, IN) ; SHAH; Jikesh Arvind; (Greenwood,
IN) ; TROMICZAK; Eric George; (Indianapolis, IN)
; WALTER; Magnus Wilhelm; (Basingstoke, GB) |
Correspondence
Address: |
ELI LILLY & COMPANY
PATENT DIVISION, P.O. BOX 6288
INDIANAPOLIS
IN
46206-6288
US
|
Assignee: |
Eli Lilly and Company
Indianapolis
IN
|
Family ID: |
42698378 |
Appl. No.: |
12/754800 |
Filed: |
April 6, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61168079 |
Apr 9, 2009 |
|
|
|
Current U.S.
Class: |
514/343 ;
546/276.4 |
Current CPC
Class: |
A61P 29/00 20180101;
A61P 25/00 20180101; C07D 401/12 20130101; A61P 25/04 20180101;
A61K 31/4439 20130101; A61P 43/00 20180101 |
Class at
Publication: |
514/343 ;
546/276.4 |
International
Class: |
A61K 31/4439 20060101
A61K031/4439; C07D 401/12 20060101 C07D401/12; A61P 29/00 20060101
A61P029/00 |
Claims
1. The compound of the formula: ##STR00085## or a pharmaceutically
acceptable salt thereof, wherein R.sup.1 is selected from the group
consisting of n-propyl, isobutyl, (C.sub.3-C.sub.4)cycloalkyl, and
(C.sub.3-C.sub.4)cycloalkyl-methyl-; n is 1 or 2; and each R.sup.2
is independently selected from the group consisting of fluoro,
chloro, bromo, methyl, ethyl, trifluoromethyl, methoxy, ethoxy,
cyclopropylmethyloxy, trifluoromethoxy, methylamino,
cyclopropylamino and t-butylcarbonylamino, provided that when n is
2, at least one of R.sup.2 is fluoro, chloro, bromo, methyl, ethyl,
trifluoromethyl, methoxy, or ethoxy.
2. The compound of claim 1 wherein R.sup.1 is n-propyl or isobutyl,
or a pharmaceutically acceptable salt thereof.
3. The compound of claim 1 wherein R.sup.1 is isobutyl, or a
pharmaceutically acceptable salt thereof.
4. The compound of claim 1 wherein R.sup.1 is
(C.sub.3-C.sub.4)cycloalkyl or (C.sub.3-C.sub.4)cycloalkyl-methyl-,
or a pharmaceutically acceptable salt thereof.
5. The compound of claim 1 which is
(S)-3-((S)-1-(6-Methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidin-
e, or a pharmaceutically acceptable salt thereof.
6. A pharmaceutical composition comprising a compound according to
claim 1, or a pharmaceutically acceptable salt thereof, in
combination with a pharmaceutically acceptable carrier, diluent, or
excipient.
7. A method of treating chronic pain in a mammal comprising
administering to a mammal in need of such treatment an effective
amount of a compound according to claim 1, or a pharmaceutically
acceptable salt thereof.
8. The method of claim 7 where the mammal is a human.
Description
[0001] Serotonin and norepinephrine have been implicated as
modulators of endogenous analgesic mechanisms in descending pain
pathways and serotonin norepinephrine reuptake inhibitors (SNRI's)
have shown efficacy in the treatment of chronic painful conditions
such as diabetic peripheral neuropathic pain and fibromyalgia
(Kroenke et al. Pharmacotherapy of chronic pain: a synthesis of
recommendations from systematic reviews, General Hospital
Psychiatry 31 (2009) 206-219 (online at
http://www.sciencedirect.com, accessed 30 Mar. 2009).
[0002] WO 2008/023258 describes certain
3-(pyrid-3-yloxymethyl)-piperidine compounds as monoamine reuptake
inhibitors (serotonin and/or norepinephrine reuptake inhibitors)
for the treatment of a wide range of disorders including pain.
[0003] US 20020151712 describes certain
3-pyrrolidinyl-oxy-3'-pyridyl ether compounds as nicotinic
acetylcholine receptor ligands for various indications including
the treatment of pain.
[0004] The present invention provides additional SNRI compounds
with greater potency and higher selectivity for serotonin and
norepinephrine reuptake than prior cited references. Additionally,
certain of the present compounds provide an improved balance of
serotonin vs. norepinephrine reuptake inhibitor activity compared
to prior cited references. Namely, prior dual activity compounds
typically have greater serotonin compared to norepinephrine
reuptake inhibitor activity, whereas certain of the presently
claimed compounds have dual activities significantly closer to the
same levels for both serotonin and norepinephrine reuptake
inhibition. Furthermore, the compounds of the present invention
provide reduced acid lability, which is generally an advantage for
improved pharmacological exposures as well as for ease of
formulation. Yet further, certain of the compounds of the present
invention provide improved metabolic degradation profiles which is
generally an advantage for improved therapeutic exposures and may
be advantageous in the reduction of pharmacological variability
within a patient population.
[0005] The present invention provides compounds of Formula I:
##STR00002##
or a pharmaceutically acceptable salt thereof, [0006] wherein
R.sup.1 is selected from the group consisting of n-propyl,
isobutyl, (C.sub.3-C.sub.4)cycloalkyl, and
(C.sub.3-C.sub.4)cycloalkyl-methyl-; [0007] n is 1 or 2; and [0008]
each R.sup.2 is independently selected from the group consisting of
fluoro, chloro, bromo, methyl, ethyl, trifluoromethyl, methoxy,
ethoxy, cyclopropylmethyloxy, trifluoromethoxy, methylamino,
cyclopropylamino and t-butylcarbonylamino, provided that when n is
2, at least one of R.sup.2 is fluoro, chloro, bromo, methyl, ethyl,
trifluoromethyl, methoxy, or ethoxy.
[0009] The invention further provides a pharmaceutical composition
comprising a compound of Formula I or a pharmaceutically acceptable
salt thereof, in combination with a pharmaceutically acceptable
carrier, diluent, or excipient. Furthermore, this invention
provides a pharmaceutical composition adapted for the treatment of
chronic pain comprising a compound of Formula I or a
pharmaceutically acceptable salt thereof in combination with one or
more pharmaceutically acceptable excipients, carriers, or diluents
thereof Further embodiments provide a pharmaceutical composition
adapted for the treatment of any one of diabetic peripheral
neuropathic pain, fibromyalgia, pain associated with fibromyalgia,
and inflammatory pain, as for example polymyalgia, rheumatoid
arthritis or osteoarthritis, comprising a compound of Formula I or
a pharmaceutically acceptable salt thereof in combination with one
or more pharmaceutically acceptable excipients, carriers, or
diluents thereof
[0010] The present invention also provides a method of treating
chronic pain in a mammal comprising administering to a mammal in
need of such treatment an effective amount of a compound of Formula
I or a pharmaceutically acceptable salt thereof Particular
embodiments of this aspect of the invention include a method of
treating diabetic peripheral neuropathic pain, a method of treating
fibromyalgia, a method of treating pain associated with
fibromyalgia, and/or a method of treating inflammatory pain, as for
example polymyalgia, rheumatoid arthritis or osteoarthritis, each
method individually comprising administering to a mammal in need of
such treatment an effective amount of a compound of Formula I, or a
pharmaceutically acceptable salt thereof In one particular
embodiment of this aspect of the invention, the mammal is a
human.
[0011] This invention also provides a compound of Formula I or a
pharmaceutically acceptable salt thereof for use in therapy. Within
this aspect, the invention provides a compound of Formula I, or a
pharmaceutically acceptable salt thereof, for use in the treatment
of chronic pain in mammals, particularly humans. Further
embodiments of this aspect of the invention include any one of the
following: a compound of Formula I, or a pharmaceutically
acceptable salt thereof, for use in the treatment of chronic pain;
a compound of Formula I, or a pharmaceutically acceptable salt
thereof, for use in the treatment of diabetic peripheral
neuropathic pain; a compound of Formula I, or a pharmaceutically
acceptable salt thereof, for use in the treatment of fibromyalgia;
a compound of Formula I, or a pharmaceutically acceptable salt
thereof, for use in the treatment of pain associated with
fibromyalgia; a compound of Formula I, or a pharmaceutically
acceptable salt thereof, for use in the treatment of inflammatory
pain; a compound of Formula I, or a pharmaceutically acceptable
salt thereof, for use in the treatment of polymyalgia; a compound
of Formula I, or a pharmaceutically acceptable salt thereof, for
use in the treatment of rheumatoid arthritis; and a compound of
Formula I, or a pharmaceutically acceptable salt thereof, for use
in the treatment of osteoarthritis.
[0012] Another aspect of this invention provides the use of a
compound of Formula I, or a pharmaceutically acceptable salt
thereof, in the manufacture of a medicament for the treatment of
chronic pain. Particular embodiments of this aspect include use of
a compound of Formula I, or a pharmaceutically acceptable salt
thereof, in the manufacture of a medicament for the treatment of
diabetic peripheral neuropathic pain; use of a compound of Formula
I, or a pharmaceutically acceptable salt thereof, in the
manufacture of a medicament for the treatment of fibromyalgia; use
of a compound of Formula I, or a pharmaceutically acceptable salt
thereof, in the manufacture of a medicament for the treatment of
pain associated with fibromyalgia; use of a compound of Formula I,
or a pharmaceutically acceptable salt thereof, in the manufacture
of a medicament for the treatment of inflammatory pain; use of a
compound of Formula I, or a pharmaceutically acceptable salt
thereof, in the manufacture of a medicament for the treatment of
polymyalgia; use of a compound of Formula I, or a pharmaceutically
acceptable salt thereof, in the manufacture of a medicament for the
treatment of rheumatoid arthritis; and use of a compound of Formula
I, or a pharmaceutically acceptable salt thereof, in the
manufacture of a medicament for the treatment of
osteoarthritis.
[0013] Compounds of this invention are bases, and accordingly react
with a number of organic and inorganic acids to form
pharmaceutically acceptable salts and the present invention
includes the pharmaceutically acceptable salts of a compound of
Formula I. The term "pharmaceutically acceptable salt" as used
herein, refers to any salt of a compound of Formula I that is
substantially non-toxic to living organisms. Such salts include
those listed in Journal of Pharmaceutical Science, 66, 2-19 (1977),
which are known to the skilled artisan.
[0014] Persistent pain is caused by chronic pathologic processes in
somatic structures or viscera, or by prolonged and sometimes
permanent dysfunction of the peripheral or central nervous system,
or by both. Persistent inflammation, tissue damage, or nerve
injury, results in hyperexcitability of dorsal horn neurons within
the spinal cord, a process also known as central sensitization.
Central sensitization is characterized by altered responsiveness of
dorsal horn neurons, the expansion of receptive fields, and
plasticity of neuronal connections within the pain transmitting
pathways. These processes lead to increased neuronal activity
within ascending pain pathways and supraspinal sites and/or to
dysfunction/disinhibition of the endogenous spinal and supraspinal
descending pain inhibitory mechanisms.
[0015] Central sensitization and disinhibition can produce an
ongoing condition of spontaneous, persistent pain as well as an
increased sensitivity to painful stimuli (hyperalgesia) or to
painful experience of normally non-painful mechanical or thermal
stimuli (allodynia). C. J. Woolf, Pain: Moving from Symptom Control
toward Mchanism-Specific Pharmacologic Management, Annals of
Internal Medicine, 140, 441-451 (2004). These processes are
postulated to underlie several types of persistent or chronic pain,
including neuropathic pain (including diabetic neuropathy,
infectious neuropathic pain associated with AIDS, non-surgical
carpal tunnel syndromes, post-herpetic neuralgia, cervical,
thoracic and lumbosacral radiculopathies, trigeminal neuralgia,
complex regional pain syndromes I and II, chemotherapy-induced
neuropathic pain and central neuropathic pain syndromes including
spinal cord injury, multiple sclerosis or stroke-related pain),
inflammatory pain (including polymyalgia, rheumatoid arthritis and
osteoarthritis), and non-neuropathic non-inflammatory pain
(including chronic fatigue syndrome, chronic back pain without
radiculopathy, fibromyalgia, chronic tension type headaches,
inflammatory bowel disorders, irritable bowel syndrome, whiplash
injuries, chronic pelvic pain including interstitial cystitis, and
temporomandibular joint disorder (TMJD)).
[0016] The recognition of the correlation between disinhibition and
an imbalance of serotonin and norepinephrine in endogenous pain
inhibitory pathways led to the successful evaluation of serotonin
and norepinphrine reuptake inhibitors in the treatment of chronic
pain conditions in man. Therefore, as dual activity inhibitors of
both serotonin and norepinephrine reuptake, the compounds of
Formula I are useful for the treatment of chronic pain, including
diabetic peripheral neuropathic pain and fibromyalgia, in mammals.
In one preferred embodiment, the mammal is a human. Furthermore,
the compounds of Formula I are useful for the treatment of
depressive disorders (including major depressive disorder), anxiety
disorders (including generalized anxiety disorder), and
incontinence (such as urge, stress and mixed-type incontinence).
(Orjales, et al., Journal of Medicinal Chemistry, 46(25), 5512-5532
(2003); Fish, et al., Bioorganic and Medicinal Chemistry Letters,
17, 2022-2025 (2007))
[0017] Abbreviations used herein are defined as follows:
[0018] "HPLC" means high-pressure liquid chromatography.
[0019] "MS (ES+)" means mass spectroscopy using electrospray
ionization.
[0020] "MTBE" means methyl t-butyl ether.
[0021] "NMR" means nuclear magnetic resonance.
[0022] "THF" means tetrahydrofuran.
[0023] "EtOAc" means ethyl acetate.
[0024] "MeOH" mean methanol
[0025] "DMSO" means dimethyl sulfoxide.
[0026] "SCX column" means strong cation exchange column.
[0027] "Pd(OAc).sub.2" means Palladium(II) acetate.
[0028] "DMF" means dimethylformamide.
[0029] "n-BuLi" means n-butyllithium
[0030] "MeOAc" means methyl acetate.
[0031] "(S)-Ru(OAc).sub.2T-BINAP" means
diacetato[(S)-(-)-2,2'-bis(di-p-tolylphosphino)-1,1'-binaphthyl]ruthenium-
(II)
[0032] "DMA" means dimethylacetamide.
[0033] "XRD" means X-Ray Diffraction.
[0034] "TOCSY" means Total Correlation Spectroscopy.
[0035] "SERT" means serotonin transporter.
[0036] "hSERT" means human serotonin transporter.
[0037] "Net" means norepinephrine transporter.
[0038] "hNet" means human norepinephrine transporter.
[0039] "DAT" means dopamine transporter.
[0040] "hDAT" means human dopamine transporter.
[0041] "HEPES" means 4-(2-hydroxyethyl)-1-piperazineethanesulfonic
acid.
[0042] "SEM" means standard errors of means. "PCA" means
para-chloroamphetamine.
[0043] ".alpha.-MMT" means Alpha-methyl-m-tyrosine.
[0044] "IC.sub.50" means half maximal inhibitory concentration.
[0045] "ED.sub.50" means effective dose.
[0046] Preferred compounds of the present invention are compounds
wherein: [0047] 1) R.sup.1 is n-propyl or isobutyl (i.e.
2-methylpropyl-); [0048] 2) R.sup.1 is isobutyl (i.e.
2-methylpropyl-); [0049] 3) R.sup.1 is n-propyl; [0050] 4) R.sup.1
is (C.sub.3-C.sub.4)cycloalkyl or
(C.sub.3-C.sub.4)cycloalkyl-methyl-; [0051] 5) R.sup.1 is
cyclopropyl or cyclopropylmethyl; [0052] 6) R.sup.1 is cyclobutyl
or cyclobutylmethyl; [0053] 7) each R.sup.2 is independently
selected from chloro, bromo, methyl, ethyl, trifluoromethyl,
methoxy, ethoxy, cyclopropylmethyloxy, and trifluoromethoxy; [0054]
8) each R.sup.2 is independently selected from chloro, bromo,
methyl, ethyl, and methoxy; [0055] 9) each R.sup.2 is independently
selected from chloro, methyl, and methoxy; [0056] 10) each R.sup.2
is independently selected from methyl, ethyl, and methoxy; [0057]
11) R.sup.1 is isobutyl and each R.sup.2 is independently selected
from chloro, bromo, methyl, ethyl, trifluoromethyl, methoxy,
ethoxy, cyclopropylmethyloxy, and trifluoromethoxy; [0058] 12)
R.sup.1 is isobutyl and each R.sup.2 is independently selected from
chloro, bromo, methyl, ethyl, and methoxy; [0059] 13) R.sup.1 is
isobutyl and each R.sup.2 is independently selected from chloro,
methyl, and methoxy; [0060] 14) R.sup.1 is isobutyl and each
R.sup.2 is independently selected from methyl, ethyl, and methoxy;
[0061] 15) R.sup.1 is n-propyl and each R.sup.2 is independently
selected from chloro, bromo, methyl, ethyl, trifluoromethyl,
methoxy, ethoxy, cyclopropylmethyloxy, and trifluoromethoxy; [0062]
16) R.sup.1 is n-propyl and each R.sup.2 is independently selected
from chloro, bromo, methyl, ethyl, and methoxy; [0063] 17) R.sup.1
is n-propyl and each R.sup.2 is independently selected from chloro,
methyl, and methoxy; [0064] 18) R.sup.1 is n-propyl and each
R.sup.2 is independently selected from methyl, ethyl, and methoxy;
[0065] 19) R.sup.1 is (C.sub.3-C.sub.4)cycloalkyl or
(C.sub.3-C.sub.4)cycloalkyl-methyl- and each R.sup.2 is
independently selected from chloro, bromo, methyl, ethyl,
trifluoromethyl, methoxy, ethoxy, cyclopropylmethyloxy, and
trifluoromethoxy; [0066] 20) R.sup.1 is (C.sub.3-C.sub.4)cycloalkyl
or (C.sub.3-C.sub.4)cycloalkyl-methyl- and each R.sup.2 is
independently selected from chloro, bromo, methyl, ethyl, and
methoxy; [0067] 21) R.sup.1 is (C.sub.3-C.sub.4)cycloalkyl or
(C.sub.3-C.sub.4)cycloalkyl-methyl- and each R.sup.2 is
independently selected from chloro, methyl, and methoxy; [0068] 22)
R.sup.1 is (C.sub.3-C.sub.4)cycloalkyl or
(C.sub.3-C.sub.4)cycloalkyl-methyl-, n is 1 or 2 and each R.sup.2
is independently selected from methyl, ethyl, and methoxy; [0069]
23) R.sup.1 cyclopropyl or cyclopropylmethyl, n is 1 or 2 and each
R.sup.2 is independently selected from chloro, bromo, methyl,
ethyl, trifluoromethyl, methoxy, ethoxy, cyclopropylmethyloxy, and
trifluoromethoxy; [0070] 24) R.sup.1 cyclopropyl or
cyclopropylmethyl, n is 1 or 2 and each R.sup.2 is independently
selected from chloro, bromo, methyl, ethyl, and methoxy; [0071] 25)
R.sup.1 cyclopropyl or cyclopropylmethyl, n is 1 or 2 and each
R.sup.2 is independently selected from chloro, methyl, and methoxy;
[0072] 26) R.sup.1 cyclopropyl or cyclopropylmethyl, n is 1 or 2
and each R.sup.2 is independently selected from methyl, ethyl, and
methoxy; [0073] 27) R.sup.1 is cyclobutyl or cyclobutylmethyl, n is
1 or 2 and each R.sup.2 is independently selected from chloro,
bromo, methyl, ethyl, trifluoromethyl, methoxy, ethoxy,
cyclopropylmethyloxy, and trifluoromethoxy; [0074] 28) R.sup.1 is
cyclobutyl or cyclobutylmethyl, n is 1 or 2 and each R.sup.2 is
independently selected from chloro, bromo, methyl, ethyl, and
methoxy; [0075] 29) R.sup.1 is cyclobutyl or cyclobutylmethyl, n is
1 or 2 and each R.sup.2 is independently selected from chloro,
methyl, and methoxy; [0076] 30) R.sup.1 is cyclobutyl or
cyclobutylmethyl, n is 1 or 2 and each R.sup.2 is independently
selected from methyl, ethyl, and methoxy; [0077] 31) For each of
above recited embodiments 7 through 30, further preferred compounds
are those wherein n is 2 and the R.sup.2 substituents are
substituted at the pyridyl 2 and 6 positions.
[0078] One particularly preferred compound of the present invention
is
(3S)-3-((S)1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidin-
e, or a pharmaceutically acceptable salt thereof, as for example
the L- and/or D-tartrate salt, as exemplified in examples 19, 19A,
and 19B.
[0079] There are two chiral centers in the compounds of Formula I,
each of which is marked with "*" below:
##STR00003##
[0080] The compounds of Formula I may, therefore, exist in a
variety of stereoisomeric configurations, such as a racemate, as
well as the diastereomers and enantiomers. Activity of the
compounds is significantly improved for compounds wherein the
chiral center at the 3-position of the pyrrolidine ring exists in
the "S" absolute configuration as required in Formula I. Compounds
may have the chiral center at the 1'-position of the appended chain
in either the "R" absolute configuration, the "S" absolute
configuration, or any mixture thereof:
##STR00004##
[0081] Generally, stereochemically pure compounds are preferred
over racemates. Generally one stereoisomer has enhanced activity
over the other. Preferred compounds are those with both chiral
centers in the "S" absolute configuration:
##STR00005##
[0082] The specific stereoisomers and enantiomers of the compound
of Formula I may be prepared by one of ordinary skill in the art
utilizing well known techniques and processes, such as those
disclosed by J. Jacques, et al., "Enantiomers, Racemates, and
Resolutions", John Wiley and Sons, Inc., 1981, and E. L. Eliel and
S. H. Wilen, "Stereochemistry of Organic Compounds",
(Wiley-Interscience 1994), and European Patent Application No.
EP-A-838448, published Apr. 29, 1998. Examples of resolutions
include recrystallization techniques or chiral chromatography.
[0083] The compounds of the present invention can be prepared
according to the following synthetic schemes by methods well known
and appreciated in the art. Suitable reaction conditions for the
steps of these schemes are well known in the art and appropriate
substitutions of solvents and co-reagents are within the skill of
the art. Likewise, it will be appreciated by those skilled in the
art that synthetic intermediates may be isolated and/or purified by
various well known techniques as needed or desired, and that
frequently, it will be possible to use various intermediates
directly in subsequent synthetic steps with little or no
purification. Furthermore, the skilled artisan will appreciate that
in some circumstances, the order in which moieties are introduced
is not critical. The particular order of steps required to produce
the compounds of the present invention is dependent upon the
particular compound being synthesized, the starting compound, and
the relative liability of the selected substituents, as is well
appreciated by the skilled chemist. Substituents R.sup.1 and
R.sup.2, unless otherwise indicated, are as previously defined, and
all reagents are well known and appreciated in the art. Pg is a
nitrogen protecting group, such as those well known in the art (see
Wuts and Greene, Greene's Protective Groups in Organic Synthesis,
4th Ed., Chapter 7, John Wiley and Sons Inc., (2007).
##STR00006##
[0084] The starting alcohol (a) is reacted with a suitable base
such as sodium hydride and an appropriately substituted aryl
fluoride in a suitable solvent, such as dimethyl sulfoxide, at
elevated temperature to provide the ether (b). Alternatively,
alcohol (a) may be reacted with an appropriately substituted
pyridine under standard Mitsunobu conditions to provide the ether
(b). The ether (b) is then de-protected under conditions well known
to the skilled artisan to provide the compound of Formula I. (For
example, see: Greene and Wuts, supra). The resulting amine may then
be treated with pharmaceutically acceptable acids, such as
L-tartaric acid, D-tartaric acid, or HCl, in a suitable solvent,
such as methanol, to provide the pharmaceutically acceptable salts
of the compounds of Formula I.
[0085] The requisite alcohol (a) may be prepared as described in
the following scheme where R.sup.1, R.sup.2 and Pg are as
previously defined.
##STR00007##
[0086] An N-protected pyrrolidine-3-carboxylic acid (c) is reacted
with N,O-dimethyl-hydroxylamine under standard amide coupling
conditions to provide the Weinreb amide (d). This amide is reacted
with a suitable organometallic nucleophile to provide the ketone
(e). Reduction of the ketone (e) under standard conditions, such as
with sodium borohydride in methanol, provides the alcohol (a).
Alternatively, an N-protected 2-pyrrolidinone (f) may be treated
with a suitable base, such as lithium bis(trimethylsilyl)amide in a
suitable solvent, such as tetrahydrofuran, and the resulting anion
is reacted with an aldehyde to provide the addition product (g).
The amide moiety is reduced under standard conditions, such as by
reaction with boron-methyl sulfide in tetrahydrofuran at elevated
temperature to provide alcohol (a).
[0087] The introduction of the 6-methoxy group into
6-methoxy-2-methyl-3-pyridyloxy pyrrolidine derivatives may be
accomplished on the free amine of the corresponding
6-chloro-2-methyl-3-pyridyloxy derivatives by nucleophilic
displacement of the chloro by a methoxide under standard
nucleophilic aromatic substitution conditions to provide the
desired compound as shown in Scheme 3.
##STR00008##
[0088] In the following preparations and examples, the designation
(S-mix) is taken to represent an intermediate or compound of
Formula I wherein the chiral center at the 3-position of the
pyrrolidine ring is in the "S" absolute configuration and the
second chiral center (referred to as 1' above) is a mixture of "S"
and "R". The designation (S-1) is taken to represent that the
corresponding intermediate or compound of Formula I is either the
first eluting enantiomer or is derived from the first eluting
enantiomer when the mixture of enantiomers was separated by
chromatography. Similarly, the designation (S-2) is taken to
represent that the corresponding intermediate or compound of
Formula I is either the second eluting enantiomer or is derived
from the second eluting enantiomer when the mixture of enantiomers
was separated by chromatography. The designation (D1) is taken to
represent an intermediate or compound of Formula I that is, or is
derived from, the first eluting diastereomer when the diastereomers
were separated by chromatography. Likewise, the designation (D2) is
taken to represent an intermediate or compound of Formula I that
is, or is derived from, the second eluting diastereomer when the
diastereomers were separated by chromatography. The designations
(D1-E1) and (D1-E2) are taken to represent an intermediate or
compound of Formula I that is, or is derived from, the first and
second eluting enantiomers, respectively, of the first-eluting
diastereomer. Likewise, the designations (D2-E1) and (D2-E2) are
taken to represent an intermediate or compound of Formula I that
is, or is derived from, the first and second eluting enantiomers,
respectively, of the second-eluting diastereomer. The exception
from these general rules is when a Mitsunobu reaction has been
undertaken with alcohol (a) leading to inversion of the
configuration of the 1' carbon. In those examples the designation
of a starting alcohol of (S-1) results in an (S-2) product and a
(D1) starting alcohol results in a (D2) product.
[0089] The following Preparations and Examples are illustrative of
methods useful for the synthesis of the compounds of the present
invention. The names for many of the compounds illustrated in the
preparations and examples are provided from structures drawn with
ChemDraw Ultra 10.0.
Preparation 1: (S)-3-(3-Methylbutanoyl)pyrrolidine-1-carboxylic
acid tert-butyl ester
##STR00009##
[0090] (S)-3-(Methoxy(methyl)carbamoyl)-pyrrolidine-1-carboxylic
acid tert-butyl ester
[0091] Add 1,1'-carbonyldiimidazole (414.33 g, 2.56 mol) portion
wise to a stirred solution of
(S)-N-tert-butoxycarbonylpyrrolidine-3-carboxylic acid (500 g, 2.32
mol) in dichloromethane (5.81 L) and stir at room temperature under
nitrogen for 1 hour. Add N,O-di-methylhydroxylamine hydrochloride
(253.04 g, 2.56 mol) and stir at room temperature for 48 hours.
Quench the reaction with 1N HCl, and extract with ethyl acetate
(2.times.). Wash the combined organics with saturated NaHCO.sub.3
and brine. Dry (MgSO.sub.4), filter and concentrate under reduced
pressure to provide 535 g (89%) of the title compound. MS (m/z)=203
(M-55).
Addition of Grignard to Weinreb Amide
[0092] Add a solution of isobutylmagnesium bromide (2.0 M in
tetrahydrofuran (THF), 63.47 mL, 126.94 mmol) in THF (50 mL) drop
wise to a stirred solution of
(S)-3-(methoxy(methyl)carbamoyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (21.86 g, 84.62 mmol) in THF (400 mL) kept under
nitrogen at -7.degree. C. Stir an hour at -5.degree. C. then allow
the reaction to warm to room temperature and continue to stir
overnight. Add saturated aqueous ammonium chloride and extract with
ethyl acetate (2.times.). Dry (MgSO.sub.4), filter and concentrate
under reduced pressure. Purify the residue by silica gel
chromatography, eluting with ethyl acetate (EtOAc) in hexane,
(0-20% gradient) to provide 21.6 g (99.6%) of the title
compound.
[0093] The compounds of Preparations 2-5 are prepared essentially
as described in
[0094] Preparation 1.
TABLE-US-00001 MS Prep. Compound Structure (m/z) 2
(S)-3-But-3-enoylpyrrolidine-1- carboxylic acid tert-butyl ester
##STR00010## 3 (S)-3-Cyclopropylcarbonyl- pyrrolidine-1-carboxylic
acid tert- butyl ester ##STR00011## 262 (M + 23) 4
(S)-3-Butanoyl-pyrrolidine-1- carboxylic acid tert-butyl ester
##STR00012## 264 (M + 23)
Preparation 5: (S)-3-Cyclobutylcarbonyl-pyrrolidine-1-carboxylic
acid tert-butyl ester
##STR00013##
[0096] Add diisobutylaluminium hydride (1M in toluene, 0.790 mL,
0.790 mmol) to a stirred mixture of magnesium (0.960 g, 39.5 mmol)
and iodine (0.100 g, 0.395 mmol) in THF (1 mL) under nitrogen. Add
drop wise a solution of cyclobutyl bromide (8.00 g, 59.2 mmol) in
THF (10 mL) and stir the reaction at 60.degree. C. for 2 h whereby
all the magnesium is consumed. Cool the mixture to room temperature
and add drop wise a solution of
(S)-3-(methoxy(methyl)carbamoyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (10.2 g, 39.5 mmol) in THF (50 mL). Stir the
reaction mixture at room temperature for 2.5 h. Quench with 1M
aqueous citric acid, extract with EtOAc. Wash the organic layer
with water and saturated aqueous NaCl, dry (Na.sub.2SO.sub.4),
filter and concentrate under reduced pressure. Purify the residue
by silica gel chromatography, eluting with EtOAc in hexanes (0-50%
gradient) to obtain the title compound (5.30 g, 53%).
Preparation 6:
(3S)-3-(1-Hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester, isomer 1 (S-1) and isomer 2 (S-2)
##STR00014##
[0098] Add sodium borohydride (15.2 g, 423 mmol) to a solution of
(S)-3-(3-methylbutanoyl)-pyrrolidine-1-carboxylic acid tert-butyl
ester (21.6 g, 84.6 mmol) in methanol (500 mL) portion wise and
stir at room temperature overnight. Add another equivalent of
sodium borohydride (3.04 g, 84.6 mmol). Stir for another 2 hours,
evaporate the methanol to half the volume, add brine and extract
with EtOAc. Dry the combined organic phases (MgSO.sub.4), filter
and concentrate under reduced pressure. Separate the
diastereoisomers by super critical fluid chromatography (AD-H
column) eluting with 10% MeOH/CO.sub.2 with 0.2% diethylmethylamine
to provide
(3S)-3-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester, isomer 1 (S-1) as the first eluting isomer (8.2
g, 38%) and
(3S)-3-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester, isomer 2 (S-2) as the second eluting isomer (8.9
g, 41%).
Preparation 7: (3S)-3-(1-Hydroxy-butyl)-pyrrolidine-1-carboxylic
acid tert-butyl ester, isomer 1 (S-1) and isomer 2 (S-2)
##STR00015##
[0100] Add sodium borohydride (5.19 g, 145 mmol) portion wise to a
solution of (S)-3-butanoyl-pyrrolidine-1-carboxylic acid tert-butyl
ester (7.0 g, 29.0 mmol) in methanol (200 mL) and stir at room
temperature over night. Add more sodium borohydride (1.4 g, 39
mmol) and stir an hour at room temperature. Evaporate the methanol
to half volume, add brine and extract with ethyl acetate. Dry the
combine organic phases (MgSO.sub.4), filter and concentrate under
reduced pressure. Separate the diastereoisomers by silica gel
chromatography eluting with 5% isopropylamine in hexanes to provide
(3S)-3-(1-hydroxy-butyl)-pyrrolidine-1-carboxylic acid tert-butyl
ester, isomer 1 (S-1) as the first eluting isomer (2.6 g, 37%) and
(3S)-3-(1-hydroxy-butyl)-pyrrolidine-1-carboxylic acid tert-butyl
ester, isomer 2 (S-2) as the second eluting isomer (1.8 g, 26%)
[0101] The compounds of Preparations 8-9 may be prepared
essentially as described in Preparation 8.
TABLE-US-00002 MS Prep. Compound Structure (m/z) 8 (3S)-3-
(Cyclopropyl(hydroxy) methyl)pyrrolidine-1- carboxylic acid
tert-butyl ester, isomer 1 (S-1) ##STR00016## 9 (3S)-3-
(Cyclopropyl(hydroxy) methyl)pyrrolidine-1- carboxylic acid
tert-butyl ester, isomer 2 (S-2) ##STR00017##
Preparation 10:
(3S)-3-(Cyclobutyl-hydroxy-methyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (S-mix)
##STR00018##
[0103] Add sodium borohyride (1.19 g, 31.4 mmol) to a stirred
solution of (S)-3-cyclobutanecarbonyl-pyrrolidine-1-carboxylic acid
tert-butyl ester (5.30 g, 20.9 mmol) in MeOH (105 mL) kept under an
atmosphere of nitrogen at 0.degree. C. Stir the mixture for 2 hours
while warming to room temperature. Concentrate the MeOH, dilute
with dichloromethane and wash the organics with saturated aqueous
NaHCO.sub.3, water and brine. Dry (MgSO.sub.4), filter and
concentrate under reduced pressure to yield the title compound (4.4
g, 82%) as a mixture of diastereomers (S-mix).
Preparation 11:
(3S)-3-(1-Hydroxy-3-butenyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester, (S-mix)
##STR00019##
[0105] The compound of Preparation 11 may be prepared essentially
as described in Preparation 10, using
(3S)-3-(but-3-enonyl)-pyrrolidine-1-carboxylic acid tert-butyl
ester.
Preparation 12:
3-(1-Hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester, diastereomer 1 (D1)
##STR00020##
[0106] 3-(1-Hydroxy-3-methyl-butyl)-2-oxo-pyrrolidine-1-carboxylic
acid tert-butyl ester, diastereomer 1 (D1) and diastereomer 2
(D2)
[0107] Add lithium bis(trimethyl silyl)-amide (1.0 M in THF, 148
mL, 148 mmol) to a solution of 2-oxo-pyrrolidine-1-carboxylic acid
tert-butyl ester (25.0 g, 134 mmol) in THF (450 mL) at -78.degree.
C. and stir under nitrogen for 2 hours. Add 3-methyl-butyraldehyde
(17.5 mL, 162 mmol) followed by boron trifluoride diethyl etherate
(20.5 mL, 162 mmol) and continue to stir at -78.degree. C. for 2
hours. Warm the mixture to room temperature, quench with saturated
aqueous ammonium chloride (250 mL) and extract with EtOAc
(3.times.). Dry the combined organics (Na.sub.2SO.sub.4), filter
and concentrate under reduced pressure. Divide the crude product
into two equal portions and purify each portion by silica gel
chromatography, eluting with 0-40% EtOAc in hexanes to provide
3-(1-hydroxy-3-methyl-butyl)-2-oxo-pyrrolidine-1-carboxylic acid
tert-butyl ester, diastereomer 1 (12.5 g, 34%) (D1) as the first
eluting isomer, MS (m/z)=216.0 (M-56), and
3-(1-hydroxy-3-methyl-butyl)-2-oxo-pyrrolidine-1-carboxylic acid
tert-butyl ester, diastereomer 2 (3.87 g, 11%) (D2) as the second
eluting isomer. MS (m/z)=216.0 (M-56)
Amide Reduction,
[0108] Slowly add boron-methyl sulfide complex (2.0 M in THF, 68.8
mL, 138 mmol) to a solution of
3-(1-hydroxy-3-methyl-butyl)-2-oxo-pyrrolidine-1-carboxylic acid
tert-butyl ester (D1) (12.5 g, 45.9 mmol) in THF (220 mL) kept
under nitrogen. Heat the mixture to reflux for 2 hours and quench
with saturated aqueous ammonium chloride (200 mL). Extract with
ethyl acetate (2.times.). Wash the combined organics with H.sub.2O
(100 mL), 5% citric acid (100 mL) and brine (100 mL). Dry
(Na.sub.2SO.sub.4), filter and concentrate under reduced pressure.
Purify the residue by silica gel chromatography eluting with 0-40%
of EtOAc in hexanes to yield 10.7 g (91%) of the title compound. MS
(m/z)=202.0 (M-56).
Preparation 13:
(3S)-3-(2-cyclopropyl-1-hydroxyethyl)pyrrolidine-1-carboxylic acid
tert butyl ester (S-mix)
##STR00021##
[0110] Add palladium (II) acetate (50.0 mg; 0.22 mmol) to a stirred
solution of (3S)-tert-butyl
3-(1-hydroxybut-3-enyl)pyrrolidine-1-carboxylate (S-mix) (3.0 g,
12.43 mmol) and freshly prepared diazomethane (50 mL, about 23 8
mmol in diethyl ether) in THF (20 mL) under nitrogen at 0.degree.
C. (Caution: vigorous gas evolution). Stir at 0.degree. C. for 10
minutes. Warm to room temperature, pour into water and extract with
ethyl acetate (3.times.). Wash the combined organics with water and
brine. Dry (MgSO.sub.4), filter and concentrate under reduced
pressure. Subject the residue to silica gel chromatography, eluting
with 0-100% ethyl acetate in hexane to afford 2.9 g (91%) of the
title compound. MS (m/z)=200.0 (M-55)
Preparation 14:
3-(2-Cyclobutyl-1-hydroxyethyl)pyrrolidine-1-carboxylic acid tert
butyl ester
##STR00022##
[0111] tert-Butyl
3-(2-(diethoxyphosphoryl)acetyl)pyrrolidine-1-carboxylate
[0112] Add butyl lithium (98.0 mL, 157 mmol) dropwise to a solution
of diethyl methylphosphonate (23.6 g, 155 mmol) in THF (194 mL)
under nitrogen at -78.degree. C. over 15 minutes. Add
(S)-3-(methoxy(methyl)carbamoyl)pyrrolidine-1-carboxylic acid tert
butyl ester (5.0 g, 19.4 mmol) in THF and stir at -78.degree. C.
for about 3.5 hrs. Pour into water and extract with ethyl acetate
(3.times.). Wash the combined organics with water and brine. Dry
(MgSO.sub.4), filter, and concentrate. Subject the residue to
silica gel chromatography, eluting with 0-50% acetone in chloroform
followed by another silica gel chromatography eluting with 0-30%
acetone in dichloromethane to afford 3.15 g (47%) of the desired
compound. MS (m/z)=294.0 (M-55)
3-(2-Cyclobutylideneacetyl)pyrrolidine-1-carboxylic acid tert butyl
ester
[0113] Add cyclobutanone (0.738 mL; 9.89 mmol) to a stirred mixture
of 3-(2-(diethoxyphosphoryl)-acetyl)pyrrolidine-1-carboxylic acid
tert butyl ester (3.14 g, 8.99 mmol) and potassium hydroxide (656
mg, 11 7 mmol) in ethanol (45 mL) kept under nitrogen at 5.degree.
C. Warm to room temperature and stir for 3 hours. Concentrate under
reduced pressure and subject the residue to silica gel
chromatography, eluting with 20% ethyl acetate in hexanes to afford
0.85 g (36%) of the crude desired compound, which is used in the
next step without further purification.
3-(2-Cyclobutylacetyl)pyrrolidine-1-carboxylic acid tert butyl
ester
[0114] Add palladium on carbon (50 mg, catalytic) to
3-(2-cyclobutylidene-acetyl)pyrrolidine-1-carboxylic acid tert
butyl ester (850 mg, 3.20 mmol) in ethyl acetate (25 mL) and stir
under nitrogen at room temperature. Install a balloon of hydrogen
gas and stir overnight. Filter the reaction over celite, rinse with
ethyl acetate and concentrate to dryness to afford 391 mg (46%) of
the desired compound. MS (m/z)=212.0 (M-55)
Reduction
[0115] Add sodium borohydride (71.9 mg, 1.90 mmol) portion wise to
3-(2-cyclobutylacetyl)pyrrolidine-1-carboxylic acid tert butyl
ester (391 mg, 1.46 mmol) in methanol (7.31 mL) at 0.degree. C.
Stir at room temperature overnight. Concentrate under reduced
pressure, dilute with water and extract with ethyl acetate
(3.times.). Wash the combined organics with saturated aqueous
NaHCO.sub.3, water and brine. Dry (MgSO.sub.4), filter and
concentrate under reduced pressure to yield 0.39 g (97%) of the
title compound. MS (m/z)=214.0 (M-55)
Preparation 15:
(3S)-3-[2-Cyclopropyl-1-(6-chloro-2-methyl-3-pyridyloxy)-ethyl]-pyrrolidi-
ne-1-carboxylic acid tert-butyl ester isomer 1 (S-1) and isomer 2
(S-2)
##STR00023##
[0117] Add sodium hydride (60%, 94.0 mg, 2.35 mmol) slowly at room
temperature to a mixture of
(3S)-3-(2-cyclopropyl-1-hydroxy-ethyl)-pyrrolidine-1-carboxylic
acid tert-butyl ester (S-mix) (31.5 g, 123.36 mmol) and DMSO (11.8
mL) kept under an atmosphere of nitrogen. Stir for 10 minutes and
then add 2-chloro-5-fluoropicoline (359 mg, 2.47 mmol). Heat to
60.degree. C. and stir overnight. Cool the mixture, pour into water
and extract with ethyl acetate (3.times.). Wash the combined
organic extracts with water and brine. Dry (MgSO.sub.4), filter and
concentrate. Purify the crude residue by silica gel chromatography,
eluting with 20% ethyl acetate in hexane to afford
(3S)-3-[2-cyclopropyl-1-(6-chloro-2-methyl-3-pyridyloxy)-ethyl]-py-
rrolidine-1-carboxylic acid tert-butyl ester, isomer 1, (S-1) (99
mg, 22%) as the first eluting isomer and
(3S)-3-[2-cyclopropyl-1-(6-chloro-2-methyl-3-pyridyloxy)-ethyl]-pyrrolidi-
ne-1-carboxylic acid tert-butyl ester, isomer 2, (S-2) (80 mg, 18%)
as the second eluting isomer. MS (m/z)=325.0 (M-55)
[0118] The compounds of Preparations 16-23 may be prepared
essentially as described in Preparation 15
TABLE-US-00003 MS Prep Compound Structure Stereo (m/z) 16
(3S)-3-[1-(2- trifluoromethyl-3- pyridyloxy)-3-methyl-
butyl]-pyrrolidine-1- carboxylic acid tert-butyl ester ##STR00024##
S-1 425 (M + Na) 17 (3S)-3-[1-(2- trifluoromethyl-3-
pyridyloxy)-3-methyl- butyl]-pyrrolidine-1- carboxylic acid
tert-butyl ester ##STR00025## S-2 425 (M + Na) 18 (3S)-3-[1-(2-
trifluoromethyl-3- pyridyloxy)-1- cyclobutyl-methyl]-
pyrrolidine-1-carboxylic acid tert-butyl ester ##STR00026## S-1
423.2 (M + 23) 19 (3S)-3-[1-(2- trifluoromethyl-3- pyridyloxy)-1-
cyclobutyl-methyl]- pyrrolidine-1-carboxylic acid tert-butyl ester
##STR00027## S-2 423.2 (M + 23) 20 (3S)-3-[1-(6-chloro-2-
methyl-3-pyridyloxy)-1- cyclobutyl-methyl]-
pyrrolidine-1-carboxylic acid tert-butyl ester ##STR00028## S-1
325.2 (M - 55) 21 (3S)-3-[1-(6-chloro-2- methyl-3-pyridyloxy)-1-
cyclobutyl-methyl]- pyrrolidine-1-carboxylic acid tert-butyl ester
##STR00029## S-2 325.2 (M - 55) 22 3-[1-(6-chloro-2-methyl-
3-pyridyloxy)-2- cyclobutyl-ethyl]- pyrrolidine-1-carboxylic acid
tert-butyl ester ##STR00030## D-1 339.2 (M - 55) 23
3-[1-(6-chloro-2-methyl- 3-pyridyloxy)-2- cyclobutyl-ethyl]-
pyrrolidine-1-carboxylic acid tert-butyl ester ##STR00031## D-2
339.2 (M - 55)
Preparation 24:
3-[1-(6-Chloro-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1-carboxylic
acid tert-butyl ester isomer 1 (D2E1) and isomer 2 (D2E2)
##STR00032##
[0119] Mitsunobu Reaction
[0120] Bubble nitrogen through a solution of
3-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (D1) (600 mg, 2.33 mmol) and
2-chloro-5-hydroxy-pyridine (0.451 g, 3.50 mmol) in toluene (10 mL)
at room temperature for 10 minutes. Add tri-n-butylphosphine (0.872
mL, 3.50 mmol) followed by azodicarboxylic acid dipiperidide (0.882
g, 3.50 mmol). Heat the reaction mixture to 70.degree. C., and stir
over night. Add additional
3-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (D1) (600 mg, 2.33 mmol), tri-n-butylphosphine
(0.872 mL, 3.50 mmol) and azodicarboxylic acid dipiperidide (0.882
g, 3.50 mmol). Continue to stir at 70.degree. C. for 3 hours. Cool
the mixture to room temperature and pour into saturated aqueous
NaHCO.sub.3. Extract with ethyl acetate (2.times.), combine the
organic extracts, dry (Na.sub.2SO.sub.4), filter and concentrate.
Purify the crude residue by silica gel chromatography eluting with
0-20% ethyl acetate in hexanes to afford 180 mg of
3-[1-(6-chloro-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1-carboxylic
acid tert-butyl ester (D2) for chiral separation.
Chiral Chromatographic Resolution.
[0121] Separate the mixture of isomers of
3-[1-(6-chloro-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1-carboxylic
acid tert-butyl ester (D2) using super critical fluid
chromatography on a OD-H column eluting with 12%
isopropylamine/CO.sub.2 with 0.2% diethylmethylamine to obtain
3-[1-(6-chloro-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1-carboxylic
acid tert-butyl ester (D2E1), as the first eluting isomer (80.6 mg,
9.4%) and
3-[1-(6-chloro-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1-carboxylic
acid tert-butyl ester (D2E2) as the second eluting isomer (81.2 mg,
9.4%).
[0122] MS (m/z)=391 [M+1].
[0123] The compounds of Preparations 25-28 may be prepared
essentially as described in Preparation 24.
TABLE-US-00004 Separation MS Prep Compound Structure Stereo
conditions (m/z) 25 3-[1-(2-Chloro-4- methyl-3- pyridyloxy)-3-
methyl-butyl]- pyrrolidine-1- carboxylic acid tert- butyl ester
##STR00033## D2E1 AD-H, 5% MeOH, 0.2% DEMA 405 (M + Na) 26
3-[1-(2-Chloro-4- methyl-3- pyridyloxy)-3- methyl-butyl]-
pyrrolidine-1- carboxylic acid tert- butyl ester ##STR00034## D2E2
AD-H, 5% MeOH, 0.2% DEMA 405 (M + Na) 27 3-[1-(2-Methyl-3-
pyridyloxy)-3- methyl-butyl]- pyrrolidine-1- carboxylic acid tert-
butyl ester ##STR00035## D2E1 OD-H, 10% MeOH, 0.2% DEMA 371 (M +
Na) 28 3-[1-(2-Methyl-3- pyridyloxy)-3- methyl-butyl]-
pyrrolidine-1- carboxylic acid tert- butyl ester ##STR00036## D2E2
OD-H, 10% MeOH, 0.2% DEMA 371 (M + Na)
Preparation 29:
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1--
carboxylic acid tert-butyl ester (S-2)
##STR00037##
[0125] Mix sodium hydride (60%, 121.2 mg, 3.03 mmol),
(3S)-3-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (S-2) (0.65 g, 2.53 mmol) and DMSO (10.0 mL). Stir
the mixture for 1 h at room temperature under an atmosphere of
nitrogen Add 2-chloro-5-fluoropicoline (2.21 g, 15.2 mmol)and stir
the mixture at 70.degree. C. overnight. Cool the mixture to room
temperature, quench the reaction with brine and extract with ethyl
acetate. Combine the organic extracts and dry (MgSO.sub.4), filter
and concentrate. Purify the crude residue by silica gel
chromatography, eluting with 0-20% ethyl acetate in hexane followed
by 20% ethyl acetate in hexane to afford 0.58 g (60%) of the title
compound. MS (m/z)=425.0 (M+23).
Preparation 30: 6-Methoxy-2-methyl-pyridin-3-ol
##STR00038##
[0127] Add hydrogen peroxide (7.69 mL, 89.8 mmol) to a stirred
mixture of 2-methoxy-6-methyl-5-pyridylboronic acid (5.0 g, 30
mmol) in dichloromethane (100 mL) kept under nitrogen at room
temperature. Stir overnight at ambient temperature, add water and
extract the mixture with dichloromethane. Combine the organic
phases, dry (MgSO.sub.4), filter and concentrate to afford 2.6 g
(62%) of the title compound. MS (m/z)=140 [M+1]
EXAMPLE 1
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidin-
e, L-tartrate (S-1)
##STR00039##
[0128] Deprotection
[0129] Add trifluoroacetic acid (1.51 g, 1.0 mL, 13 2 mmol) to a
solution of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrol-
idine-1-carboxylic acid tert-butyl ester (S-1) (99.0 mg, 0.260
mmol) in methoxybenzene (1.0 mL) and dichloromethane (2.0 mL). Stir
under nitrogen at room temperature for 1 h. Load the mixture
directly onto a pre-packed SCX column and rinse with
CH.sub.2Cl.sub.2 followed by CH.sub.3OH. Elute with 2M NH.sub.3 in
methanol and concentrate under reduced pressure to give 58 mg (79%)
of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne (S-1). MS (m/z)=281.2 [M+1]
Salt Formation
[0130] Add L-tartaric acid (31.0 mg, 0.207 mmol) to a solution of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne (S-1) (58.0 mg, 0.207 mmol) in methanol (2 mL). Stir the mixture
at room temperature for an hour under nitrogen. Concentrate and dry
in a vacuum oven to obtain 89.0 mg (99%) of the title compound.
[0131] MS (m/z)=281.0 [M+1]
[0132] The compounds of EXAMPLES 2-8 may be prepared essentially as
described in EXAMPLE 1.
TABLE-US-00005 MS, Ex. Compound Structure Stereo (m/z) 2
3-[1-(2-Chloro-4-methyl- 3-pyridyloxy)-3-methyl-
butyl]-pyrrolidine, L- tartrate ##STR00040## D2E2 283 [M + 1] 3
3-[1-(6-Chloro-3- pyridyloxy)-3-methyl- butyl]-pyrrolidine, L-
tartrate ##STR00041## D2E2 269 [M + 1] 4 (3S)-3-[1-(2-
trifluoromethyl-3- pyridyloxy)-3-methyl- butyl]-pyrrolidine, L-
tartrate ##STR00042## S-1 303 [M + 1] 5 3-(3-Methyl-1-(2-methyl- 3-
pyridyloxy)butyl) pyrrolidine, L-tartrate ##STR00043## D2E2 249 [M
+ 1] 6 (3S)-3-(cyclobutyl(2- (trifluoromethyl)-3-
pyridyloxy)methyl) pyrrolidine, L-tartrate ##STR00044## S-1 301 [M
+ 1] 7 (3S)-3-(cyclobutyl-(6- chloro-2-methyl-3- pyridyloxy)methyl)
pyrrolidine, L-tartrate ##STR00045## S-1 281.2 [M + 1] 8
3-(2-cyclobutyl-1-(6- chloro2-methyl-3- pyridyloxy)-
ethyl)pyrrolidine, L- tartrate ##STR00046## D1 295.0 [M + 1]
EXAMPLE 9
(3S)-3-(3-Methyl-1-(2-methyl-6-methylamino-3-pyridyloxy)butyl)-pyrrolidine-
, L-tartrate (S-2)
##STR00047##
[0133] Pd-Catalyzed Coupling Reaction
[0134] Charge a 5 mL microwave vessel with 0.294 mL of a 10 mg/mL
solution of Pd(OAc).sub.2 (2.93 mg, 0.013 mmol) in toluene. Add
0.756 mL of a 10 mg/mL solution of cataCXium@PtB from Degussa
[(N-Phenyl-2-(di-t-butylphosphino)pyrrole] (7.50 mg, 0.026 mmol) in
toluene and sodium tert-butoxide (30.2 mg, 0.314 mmol) under an
atmosphere of nitrogen. Add 1 mL of a 10 mg/mL solution of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1--
carboxylic acid tert-butyl ester (S-2) (0.100 g, 0.261 mmol) in
toluene and methylamine (0.392 mL, 0.785 mmol). Heat the reaction
mixture at 150.degree. C. for 1.5 hours. Add Si--SH resin and stir
for 2 hours to scavenge the Pd. Pour the crude mixture onto a
pre-packed SCX-column washed with methanol, release the product
with 2M NH.sub.3 in methanol and concentrate. The crude product is
used in the next step without further purification. MS (m/z)=378
[M+1]
Deprotection
[0135] Stir a mixture of
(3S)-3-[1-(2-methyl-6-methylamino-3-pyridyloxy)-3-methyl-butyl]-pyrrolidi-
ne-1-carboxylic acid tert-butyl ester (S-2) and aqueous HCl (4M,
0.261 mL, 1.04 mmol) at room temperature for 1 hour. After full
conversion, concentrate the mixture, dissolve in dichloromethane
and load the mixture onto a pre-packed SCX column. Wash with
dichloromethane followed by methanol. Release the product with 2M
NH.sub.3 in methanol and concentrate under reduced pressure. Purify
the crude residue by reverse phase chromatography (17-43% gradient
actonitrile in 0.01 M ammoniumformate in water, 85 mL/min, for 8
min., C.sup.18 ODB XBridge column, 30.times.75 mm, 5 .mu.m) to give
9 mg (12%) of
(3S)-3-[1-(2-methyl-6-methylamino-3-pyridyloxy)-3-methyl-butyl]-pyrrolidi-
ne (S-2). MS (m/z)=278 [M+1].
[0136] Prepare the L-tartrate salt by dissolving the purified
material into a mixture of acetonitrile/methanol (5:1). Add a 1N
aqueous solution of L-tartaric acid (1.05 equiv). Lyophilize the
mixture to afford the title compound as a solid. MS (m/z)=278
[M+1.
EXAMPLE 10
(3S)-3-[1-(6-cyclopropylamino-2-methyl-3-pyridyloxy)-3-methyl-butyl]-pyrro-
lidine, L-tartrate (S-2)
##STR00048##
[0138] The title compound may be prepared essentially as described
in EXAMPLE 9. MS (m/z)=304 [M+1].
EXAMPLE 11
(3S)-3-(1-(6-ethoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidine,
L-tartrate (S-2)
##STR00049##
[0139] Pd-Catalyzed Coupling Reaction
[0140] Charge a 5 mL microwave vessel with
(S)-(-)-2,2'-bis(di-p-tolylphosphino)-1,1'-binaphthyl (15.1 mg,
0.0222 mmol), tris(dibenzylideneacetone)dipalladium (0) (10.2 mg,
0.0111 mmol) and toluene (2 mL). Add a solution of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1--
carboxylic acid tert-butyl ester (S-2) (85.0 mg, 0.222 mmol) in
toluene (1 mL) followed by sodium ethoxide (0.216 mg, 0.666 mmol).
The reaction mixture is irradiated under microwave conditions at
140.degree. C. for 30 minutes. Add Si--SH resin and stir for 2
hours to scavenge the Pd. Pour the crude mixture onto an
SCX-column, wash with methanol, release the product with 2M
NH.sub.3 in methanol and concentrate. The crude product is used in
the next step without further purification. MS (m/z)=393 [M+1]
Deprotection
[0141] Stir a mixture of
(3S)-3-[1-(6-ethoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1--
carboxylic acid tert-butyl ester (S-2) and aqueous HCl (4N in
dioxane, 0.261 mL, 1.04 mmol) at room temperature for 1 hour. After
full conversion, concentrate the mixture, dissolve the residue in
chloromethane and load onto a pre-packed SCX column. Wash the
column with dichloromethane followed by methanol. Release the
product with 2M NH.sub.3 in methanol and concentrate under reduced
pressure. Purify the crude residue by reverse phase chromatography
(34-60% gradient actonitrile in 0.01 M ammoniumformate in water, 85
mL/min, for 8 min., C.sup.18 ODB XBridge column, 30.times.75 mm, 5
.mu.m) to give 13.4 mg (21%) of
(3S)-3-[1-(6-ethoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl]-pyrro-
lidine (S-2). MS (m/z)=293 [M+1].
[0142] Prepare the L-tartrate salt by dissolving the purified
material into a mixture of acetonitrile/methanol (5:1). Add a 1N
aqueous solution of L-tartaric acid (1.05 equiv). Lyophilize the
mixture to afford the title compound as a solid. MS (m/z)=293
[M+1].
EXAMPLE 12
(3S)-3-(1-(6-chloro-2-methyl-3-pyridyloxy)butyl)-pyrrolidine,
L-tartrate (S-2)
##STR00050##
[0144] Add (3S)-3-(1-hydroxy-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (S-2) (0.400 g, 1.64 mmol) and sodium hydride
(60%, 132 mg, 3.29 mmol) to DMSO (10 mL). Keep the mixture under an
atmosphere of nitrogen and stir for 15 minutes. Add
6-chloro-3-fluoropicoline (1.44 g, 9.86 mmol). Heat the mixture to
70.degree. C. and stir for 1 hour. Pour the reaction mixture onto
brine and extract with EtOAc. Combine the extracts and dry (MgSO4),
filter and concentrate. Use the crude residue in the next reaction
without further purification.
[0145] The deprotection and L-tartrate formation are essentially
performed as in EXAMPLE 1 to afford the title compound (384 mg,
56%). MS (m/z)=268 [M+1].
[0146] The compounds of EXAMPLES 13-16 may be prepared essentially
as described in EXAMPLE 12.
TABLE-US-00006 MS, Ex. Compound Structure Stereo (m/z) 13
(3S)-3-[1-(6-Chloro-2- methyl-3-pyridyloxy)- 3-methyl-butyl]-
pyrrolidine, L-tartrate ##STR00051## S-2 269 [M + 1] 14
(3S)-3-[1-(6-Bromo-2- methyl-3-pyridyloxy)- 3-methyl-butyl]-
pyrrolidine, L-tartrate ##STR00052## S-2 314 [M + 1] 15
(3S)-3-[1-(2-Bromo-6- methyl-3-pyridyloxy)- 3-methyl-butyl]-
pyrrolidine, L-tartrate ##STR00053## S-2 328 [M + 1] 16
(3S)-3-[1-(6-Chloro-2- methyl-3-pyridyloxy)- 1-cyclopropylmethyl]-
pyrrolidine, L-tartrate ##STR00054## S-2 267 [M + 1]
EXAMPLE 17
(3S)-3-(1-(6-bromo-3-pyridyloxy)-3-methyl-butyl)-pyrrolidine,
L-tartrate (S-2)
##STR00055##
[0148] Charge a reaction vessel with a solution of
(3S)-3-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (S-2) (100 mg, 0.389 mmol) in DMF (3 mL). Add
3-fluoro-6-bromo-3-pyridine (90 mg, 0.051 mmol), 18-crown-6 (10.3
mg, 0.039 mmol) and sodium tert-butoxide (68.2 mg, 0.699 mmol).
Heat the reaction at 80.degree. C. for several hours until the
LC/MS shows conversion to the desired product. Evaporate the
solvent and use the residue in the next reaction without further
purification.
[0149] The deprotection and the salt formation are essentially
performed as in EXAMPLE 11 to afford the title compound. MS
(m/z)=314 [M+1].
EXAMPLE 18
(3S)-3-[1-(6-Chloro-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine,
L-tartrate (S-2)
##STR00056##
[0151] The title compound may be prepared essentially as described
in EXAMPLE 17. MS (m/z)=269 [M+1].
EXAMPLE 19
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidine,
L-tartrate (S-2)
##STR00057##
[0153] Purge nitrogen through a solution of
(3S)-3-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (S-1) (0.5 g, 1.94 mmol) and
6-methoxy-2-methyl-pyridin-3-ol (0.41 g, 2.91 mmol) in toluene (10
mL) at room temperature for 10 minutes. Add tri-n-butylphosphine
(0.73 mL, 2.91 mmol) followed by azodicarboxylic acid dipiperidide
(0.59 mg, 2.91 mmol). Heat the reaction mixture to 70.degree. C.,
and stir over night. Cool the mixture to room temperature and pour
onto saturated aqueous NaHCO.sub.3 (50 mL). Extract with ethyl
acetate (2.times.), combine the organic extracts and dry
(Na.sub.2SO.sub.4), filter and concentrate. Purify the crude
residue by silica gel chromatography eluting with 0-20% ethyl
acetate in hexanes to afford
(3S)-3-[1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl]-pyrrolidine-1-
-carboxylic acid tert-butyl ester (S-2) (101 mg, 13%). The
deprotection and the L-tartarte formation are performed essentially
as in EXAMPLE 1 to afford the title compound. MS (m/z)=279
[M+1]
EXAMPLE 19A
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidine,
(S-2). Alternative Synthesis
##STR00058##
[0154] (S)-1-Benzyl-3-(3-methylbutanoyl)pyrrolidin-2-one
[0155] Charge a 5 L, 3-neck round bottom flask equipped with a
magnetic stirrer, thermal couple, addition funnel and N.sub.2 inlet
with diisopropylamine (176 mL, 1265 mmoles) and
2-methyltetrahydrofuran (500 mL). Cool the solution to
.about.-10.degree. C. (salt/ice bath) with stirring and add a
solution of n-BuLi (2.5 M in hexanes, 504 mL, 1259 mmoles) drop
wise while maintaining a temperature at or below 0.degree. C. Rinse
the addition funnel with 2-methyltetrahydrofuran (25 mL). Stir the
solution for about 15 min, at .about.-5.degree. C. Add a solution
of N-benzyl-2-pyrrolidinone (100.8 g, 575 2 mmoles), ethyl
isovalerate (90 g, 690 mmoles) in 2-Me-THF (500 mL) drop wise at a
rate to maintain a temperature at or below 5.degree. C. to provide
a yellow slurry. Stir the reaction mixture about 1 hour at
-5.degree. C., add heptane (1 L) drop wise, and stir for an
additional 1 hr. at -5.degree. C. Collect the solid by filtration
through a medium fritted funnel, wash with a 1:1 solution of
2-methyltetrahydrofuran/heptane (250 mL) followed by heptane (250
mL) and air dry until the solid becomes powder-like. Place the
yellow solid into a 5 L, 3-neck round bottom flask equipped with a
magnetic stirrer and add MTBE (1 L) and 10% citric acid (1 L). Stir
the mixture for about 1 hour at room temperature to provide a
homogeneous mixture. Separate the layers and wash the organic layer
with H.sub.2O (2.times.500 mL), followed by brine (500 mL). Dry
over Na.sub.2SO.sub.4, filter and concentrate to give the crude
intermediate (128 g) as an orange oil. A Kuegelrohr distillation
removes the major impurity from the crude material to yield the
desired intermediate as a dark orange oil (117.4 g, 452.7 mmoles,
78.7% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.38-7.16
(m, 5H), 4.55-4.35 (m, 2H), 3.62 (dd, 1H, J=5.86, 9.37 Hz),
3.38-3.14 (m, 2H), 2.92-2.8 (m, 1H), 2.64-2.42 (m, 2H), 2.28-2.11
(m, 1H), 2.08-1.93 (m, 1H), 0.96 (d, 3H, J=7.03 Hz) 0.93 (d, 3H,
J=7.04 Hz). GC/MS=260 (M+1).
(R)-1-Benzyl-3-((S)-1-hydroxy-3-methylbutyl)pyrrolidin-2-one
[0156] Charge a 400 mL stainless steel autoclave vessel with a
solution of (S)-1-benzyl-3-(3-methylbutanoyl)pyrrolidin-2-one (20
g, 77.12 mmoles) in IPA (250 mL), followed by 35% HCl (6% compared
to the substrate, 4.63 mmoles, M=36.4 g/mol, d=1.18 g/mL, 0.408
mL). Purged with N.sub.2 gas (5.times..about.50 PSI). Vent the
vessel and quickly add (S)-Ru(OAc).sub.2T-BINAP (250 mg, 0.2784
mmoles), while a stream of N.sub.2 flows over the top of the
reaction mixture Immediately seal the autoclave and purge with
N.sub.2 gas (5.times..about.50 PSI). Purge the vessel with H.sub.2
gas (5.times.60 PSI) and then charge of the vessel with H.sub.2 gas
(60 PSI). Stir the reaction mixture at 65.degree. C. overnight
(.about.16-18 hours). The pressure of the vessel increases to
.about.70 PSI during this time and the vessel is refilled with
H.sub.2 gas as needed and not kept at a constant pressure of 60 PSI
over the course of the reaction. Cool to room temperature and
concentrate under reduced pressure to give crude
(R)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)pyrrolidin-2-one as a
dark brown oil that was taken onto the next step without further
purification (21.6 g, 82.6 mmoles, .about.95-97% ee, >100%
yield). .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.38-7.18 (m,
5H), 4.48 (s, 2H), 4.34-4.22 (m, 1H), 3.28-3.14 (m, 2H), 2.63 (td,
1H, J=2.93, 9.37 Hz), 2.47 (d, 1H, J=5.86 Hz), 2.12-1.70 (m, 3H),
1.54-1.38 (m, 1H), 1.24-1.10 (m, 1H), 0.95 (d, 3H, J=3.51 Hz), 0.93
(d, 3H, J=2.93 Hz). GC/MS=262 (M+1).
(S)-1-Benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine
[0157] Charge a 1 L, 3-neck round bottom flask equipped with a
magnetic stirrer, thermal couple, addition funnel and N.sub.2 inlet
with crude
(R)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)pyrrolidin-2-one (38.26
mmoles, assumed) and toluene (100 mL). Cool the slightly
heterogeneous stirring solution to 0.degree. C. (salt/ice bath) and
add a solution of Vitride.TM. (Rohm & Haas) (65 wt % in
toluene, 24 mL, 86.085 mmoles) and toluene (70 mL) drop wise while
maintaining a temperature at or below 5.degree. C. Rinse the
addition funnel with toluene (10-20 mL). Stir at room temperature
overnight (.about.16 hr). Cool the reaction mixture to 0.degree. C.
(salt/ice bath) and quenched with saturated Rochell's salt solution
(200 mL) followed by MTBE (200 mL). Allow the mixture to warm to
room temperature with stirring and then stir at this temperature
for 1 hour. Separate the organic and aqueous layers and wash the
organic layer with H.sub.2O (2.times.200 mL), then brine (200 mL),
and then dry over Na.sub.2SO.sub.4. Filter and concentrate to give
the desired intermediate as a brown oil (9.61 g, 38.85 mmoles,
>100% yield). .sup.1H NMR (300 MHz, CDCl.sub.3) .delta.
7.36-7.18 (m, 5H), 3.82-3.72 (m, 1H), 3.58 (dd, 2H, 7.61, 20.51
Hz), 2.87 (td, 1H, J=4.10, 8.79 Hz), 2.79-2.70 (m, 1H), 2.48-2.38
(m, 1H), 2.26-2.04 (m, 2H), 1.98-1.64 (m, 3H), 1.46-1.32 (m, 1H),
1.14-0.98 (m, 1H), 0.92 (d, 3H, J=1.18 Hz), 0.89 (d, 3H, J=1.76
Hz). LC/MS=248.1 (M+1).
Resolution/Purification of
(S)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine
[0158] Charge a 500 mL round bottom flask equipped with a magnetic
stir bar and N.sub.2 inlet with crude
(S)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine (9.61g,
38.26 mmoles) and MeOAc (96 mL). Add dibenzoyl-(L)-tartaric acid
(13.71 g, 38.26 mmoles) in one portion with stirring and allow the
reaction mixture to stir at room temperature until the mixture
becomes cloudy (.about.5 min.). Heat in a preheated oil bath at
50.degree. C. overnight with stirring (.about.16 hours). Cool the
reaction mixture to room temperature and isolate the solid by
filtration through a medium fritted funnel Wash the solid with
methyl acetate (5.times.20 mL) and allow to air dry to give
(S)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine salt as a
white solid (15.1 g, 24.93 mmoles, 65.2% yield over 3 steps, 81.4%
isomer recovery assuming 80% ee). LC/MS=248.1 (M+1).
Desalting of
(S)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine salt
[0159] Charge a 500 mL round bottom flask equipped with a magnetic
stir bar with
(S)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine salt
(13.71 g, 22.636 mmoles) and MTBE (140 mL). Add aqueous saturated
NaHCO.sub.3 (140 mL) and stir the heterogeous mixture at room
temperature overnight. Dilute the cloudy solution with EtOAc (140
mL) and aqueous saturated NaHCO.sub.3 (50 mL), followed by H.sub.2O
(.about.100 mL), to provide a clear mixture. Separate the layers
and dry the organic layer over Na.sub.2SO.sub.4. Filter and
concentrate to give
(S)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine as a tan
oil that was taken onto the next step without further purification
(5.37 g, 21.707 mmoles, 95.9% recovery)..sup.1H NMR (300 MHz,
CDCl.sub.3) .delta. 7.36-7.18 (m, 5H), 3.82-3.72 (m, 1H), 3.58 (dd,
2H, 7.61, 20.51 Hz), 2.87 (td, 1H, J=4.10, 8.79 Hz), 2.79-2.70 (m,
1H), 2.48-2.38 (m, 1H), 2.26-2.04 (m, 2H), 1.98-1.64 (m, 3H),
1.46-1.32 (m, 1H), 1.14-0.98 (m, 1H), 0.92 (d, 3H, J=1.18 Hz), 0.89
(d, 3H, J=1.76 Hz). LC/MS=248.1 (M+1).
(S)-1-benzyl-3-((S)-1-(6-chloro-2-methyl-3-pyridyloxy)-3-methylbutyl)-pyrr-
olidine
[0160] Charge a 200 mL round bottom flask equipped with a Claisen
adaptor, thermal couple and N.sub.2 inlet with
(S)-1-benzyl-3-((S)-1-hydroxy-3-methylbutyl)-pyrrolidine (5.69 g,
23 mmoles) and DMA (58 mL). Add NaH (1.29 g, 32.2 mmoles) in one
portion with stirring and stir at room temperature for 1 hour. Add
6-chloro-3-fluoro-2-methylpyridine (3.52 g, 24.15 mmoles) in one
portion with stirring and then stir at room temperature for 24
hours. Quench the reaction mixture with H.sub.2O (120 mL) and
extract with MTBE (120 mL). Wash the organic layer with H.sub.2O
(2.times.60 mL), followed by brine (60 mL), and then dry over
Na.sub.2SO.sub.4. Filter, concentrate, and then purify the crude
material (in toluene) by loading onto silica (225 g, wet with
toluene) and eluting with the following: hexanes (2.times.500 mL),
15% MTBE/hexanes (16.times.500 mL), 50% MTBE/hexanes (8.times.500
mL). Concentrate the appropriate fractions to give
(S)-1-benzyl-3-((S)-1-(6-chloro-2-methyl-3-pyridyloxy)-3-methylbutyl)-pyr-
rolidine as a light yellow oil (5.77 g, 15.47 mmoles, 67% yield,
purity >98%). .sup.1H NMR (300 MHz, CDCl.sub.3) .delta.
7.38-7.20 (m, 5H), 7.06 (s, 2H), 4.32-4.20 (m, 1H), 3.68-3.48 (m,
2H) 2.78-2.64 (m, 2H), 2.64-2.30 (m, 2H), 2.42 (s, 3H), 2.28-2.20
(m, 1H), 2.05-1.85 (m, 1H), 1.82-1.52 (m, 4H), 1.48-1.34 (m, 1H),
0.92 (d, 3H, J=6.45 Hz), 0.88 (d, 3H, J=6.45 Hz). LC/MS=373.2 (M),
375.3 (M+2).
(S)-1-benzyl-3-((S)-1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methylbutyl)-pyr-
rolidine
[0161] To a 200 mL RB flask equipped with a magnetic stir bar and
N.sub.2 inlet was charged with
(S)-1-benzyl-3-((S)-1-(6-chloro-2-methyl-3-pyridyloxy)-3-methylbutyl)-pyr-
rolidine (5.46 g, 14.65 mmoles) and DMSO (30 mL). Add potassium
methoxide (4.11 g, 58.61 mmoles) in one portion with stirring. Stir
the reaction mixture in an oil bath at 100.degree. C. for 1 hour.
Dilute with H.sub.2O (60 mL) and MTBE (60 mL). Separate the layers
and wash organic layer with H.sub.2O (2.times.30 mL), followed by
brine (30 mL), and then dry over Na.sub.2SO.sub.4. Filter and
concentrate the crude material (in toluene). Load onto silica (225
g, wet with toluene), and elute with the following: hexanes
(2.times.500 mL), 50% MTBE/hexanes (6.times.500 mL). Concentrate
the appropriate fractions to give
(S)-1-benzyl-3-((S)-1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methylbutyl)-py-
rrolidine. (4.32 g, 11.72 mmoles, 80% yield) as a yellow/orange
oil. .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.34-7.2 (m, 5H),
7.10 (d, 1H, J=8.79 Hz), 6.49 (d, 1H, J=8.79), 4.17-4.07 (m, 1H),
3.88 (s, 3H), 3.68-3.50 (m, 2H), 2.78-2.67 (m, 2H), 2.61-2.48 (m,
1H), 2.48-2.38 (m, 1H), 2.37 (s, 3H), 2.33-2.24 (m, 1H), 2.00-1.50
(m, 5H), 1.44-1.30 (m, 1H), 0.885 (at, 6H, J.sub.a=7.03 Hz,
J.sub.b=6.44 Hz). LC/MS=369.3 (M+1).
(S)-3-((S)-1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methylbutyl)-pyrrolidine
[0162] Charge a 400 mL stainless steel autoclave with 20% by weight
Pd/C (10%, wet, 820 mg) followed by a solution of
(S)-1-benzyl-3-((S)-1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methylbutyl)-py-
rrolidine (4.1 g, 11.126 mmoles) in ethanol (82 mL). Purge with
H.sub.2 gas (3.times.50 PSI), then charge the vessel with H.sub.2
gas (50 PSI). Heat the reaction mixture to 60.degree. C..sup.1 and
stir at 60.degree. C. for 24 hours. The pressure of the vessel
increases to .about.55 PSI at 60.degree. C. and the vessel is
refilled with H.sub.2 gas as needed. Allow the reaction mixture to
cool to room temperature, filter through a medium fritted funnel
charged with celite (wet with ethanol), and wash with ethanol
(.about.80 mL). Concentrate under reduced pressure to give
(S)-3-((S)-1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methylbutyl)-pyrrolidine
as a light yellow oil (3.02 g, 10.848 mmoles, 97.5% yield). .sup.1H
NMR (300 MHz, CDCl.sub.3) .delta. 7.12 (d, 1H, J=8.79 Hz), 6.50 (d,
1H, 8.79 Hz), 4.2 (aq, 1H, J.sub.a=7.03 Hz, J.sub.b=5.27 Hz), 3.87
(s, 3H), 3.08-2.94 (m, 2H), 2.94-2.82 (m, 1H), 2.82-2.70 (m, 1H),
2.50-2.26 (m, 3H), 2.36 (s, 3H), 1.94-1.78 (m, 1H), 1.78-1.52 (m,
3H), 1.44-1.30 (m, 1H), 0.898 (at, 6H, J.sub.a=6.45 Hz,
J.sub.b=7.03 Hz). LC/MS=279.3 (M+1).
EXAMPLE 19B
(S)-3-((S)-1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidine-
, D-tartrate
##STR00059##
[0164] Dissolve
(S)-3-((S)-1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidin-
e (353 mg) is dissolved in THF (1 mL) at 60.degree. C. while
stirring at 1000 rpm. A slightly cloudy yellow solution results.
Slowly add a solution of D-tartaric acid (218 mg dissolved in 3 mL
THF at 80.degree. C.) to the solution. Filter the solution through
a 0.45 .mu.m PTFE syringe filter and add acetonitrile (4 mL). Allow
to evaporate, lidless, in a hood. A large amount of off-white solid
precipitates after about 20 min. vacuum filter the solution and dry
the solids in a 60.degree. C. vacuum oven for 1 hr. to obtain a
powdery off-white solid.
X-Ray Powder Diffraction
[0165] The XRD pattern of the crystalline is obtained on a Bruker
D8 Advance X-ray powder diffractometer, equipped with a CuK.alpha.
source .lamda.=1.54056 .ANG.) and a Vantec detector, operating at
50 kV and 40 mA. The sample is scanned between 4 and 40.degree. in
2.theta., with a step size of 0.02.degree. in 2.theta. and a scan
rate of 9.0 seconds/step, and with 1 mm divergence and receiving
slits and a 0.1 mm detector slit. The dry powder is packed into
recessed top-loading sample holder and a smooth surface is obtained
using a glass slide. The crystal form diffraction patterns are
collected at ambient temperature and relative humidity. The
background is removed prior to peak picking. It is well known in
the crystallography art that, for any given crystal form, the
relative intensities of the diffraction peaks may vary due to
preferred orientation resulting from factors such as crystal
morphology and habit. Where the effects of preferred orientation
are present, peak intensities are altered, but the characteristic
peak positions of the polymorph are unchanged. See, e.g. , The
United States Pharmacopeia #23, National Formulary #18, pages
1843-1844, 1995. Furthermore, it is also well known in the
crystallography art that for any given crystal form the angular
peak positions may vary slightly. For example, peak positions can
shift due to a variation in the temperature or humidity at which a
sample is analyzed, sample displacement, or the presence or absence
of an internal standard. In the present case, a peak position
variability of .+-.0.1 in 2.theta. will take into account these
potential variations without hindering the unequivocal
identification of the indicated crystal form. Confirmation of a
crystal form may be made based on any unique combination of
distinguishing peaks (in units of .degree. 2.theta.), typically the
more prominent peaks. Thus, a prepared sample of the d-tartrate
salt of
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidine
is characterized by an XRD pattern using CuK.alpha. radiation as
having diffraction peaks (2-theta values) as described in Table 1
below, and in particular having peaks at 4.63 in combination with
one or more of the peaks selected from the group consisting of
9.26, 16.12, and 16.59; with a tolerance for the diffraction angles
of 0.1 degrees.
TABLE-US-00007 TABLE 1 X-ray powder diffraction peaks of the
d-tartrate salt of
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-3-methyl-butyl)-pyrrolidine.
Angle d value Intensity % 2-Theta .degree. Angstrom % 4.63 19.06
100 9.26 9.55 20 12.22 7.23 19 13.87 6.38 14 16.12 5.49 86 16.59
5.34 38 17.85 4.96 12 18.55 4.78 20 18.88 4.70 21 20.21 4.39 18
21.56 4.12 11 22.45 3.96 15 23.23 3.83 23 24.11 3.69 17 24.55 3.62
12 25.63 3.47 12 26.48 3.36 15 26.64 3.34 10
[0166] The compounds of EXAMPLES 20-32 may be prepared essentially
as described in EXAMPLE 19.
TABLE-US-00008 MS, Ex. Compound Structure Stereo (m/z) 20
(3S)-3-[1-(2-Chloro-3- pyridyloxy)-3-methyl- butyl]-pyrrolidine,
L-tartrate ##STR00060## S-2 269 [M + 1] 21
(3S)-3-[1-(2,6-Dimethyl-3- pyridyloxy)-3-methyl-
butyl]-pyrrolidine, L-tartrate ##STR00061## S-2 263 [M + 1] 22
(3S)-3-[1-(6-Methoxy-3- pyridyloxy)-3-methyl- butyl]-pyrrolidine,
L-tartrate ##STR00062## S-2 265 [M + 1] 23 (3S)-3-[1-(6-Methyl-3-
pyridyloxy)-3-methyl- butyl]-pyrrolidine, L-tartrate ##STR00063##
S-2 249 [M + 1] 24 (3S)-3-[1-(2-Chloro-6- methyl-3-pyridyloxy)-3-
methyl-butyl]-pyrrolidine, L-tartrate ##STR00064## S-2 283 [M + 1]
25 (3S)-3-[1-(6-Chloro-4- methyl-3-pyridyloxy)-3-
methyl-butyl]-pyrrolidine, L-tartrate ##STR00065## S-2 283 [M + 1]
26 (3S)-3-[1-(2-Ethyl-6- methyl-3-pyridyloxy)-3-
methyl-butyl]-pyrrolidine, L-tartrate ##STR00066## S-2 277 [M + 1]
27 (3S)-3-[1-(2-Fluoro-6- methyl-3-pyridyloxy)-3-
methyl-butyl]-pyrrolidine, L-tartrate ##STR00067## S-2 267 [M + 1]
28 (3S)-3-[1-(2-Methoxy-6- methyl-3-pyridyloxy)-3-
methyl-butyl]-pyrrolidine, L-tartrate ##STR00068## S-2 279 [M + 1]
29 (3S)-3-[1-(2,6-Dichloro-3- pyridyloxy)-3-methyl-
butyl]-pyrrolidine, L-tartrate ##STR00069## S-2 303 [M + 1] 30
(3S)-3-[1-(2-Tert- butylcarbonylamino-3- pyridyloxy)-3-methyl-
butyl]-pyrrolidine, L-tartrate ##STR00070## S-2 334 [M + 1] 31
(3S)-3-[1-(2-Ethoxy-3- pyridyloxy)-3-methyl- butyl]-pyrrolidine,
L-tartrate ##STR00071## S-2 279 [M + 1] 32 (3S)-3-[1-(2-
cyclopropylmethyloxy-3- pyridyloxy)-3-methyl- butyl]-pyrrolidine,
L-tartrate ##STR00072## S-2 305 [M + 1]
EXAMPLE 33
3-(1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclobutyl-ethyl)-pyrrolidine,
L-tartrate (D1E2)
##STR00073##
[0167] De-Salting.
[0168] Pour
3-(1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclobutyl-ethyl)-pyrrolidine,
L-tartrate (D1) (80.0 mg, 0.180 mmol) onto an SCX column and rinse
with dichloromethane, 50% dichloromethane in methanol and methanol.
Elute the compound with 2M NH.sub.3 in methanol and concentrate to
afford
3-(1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclobutyl-ethyl)-pyrrolidine
(50 mg).
Chiral Chromatographic Resolution
[0169] Subject the amine (50 mg) to supercritical fluid chiral
chromatography (Chiracel OD-H) eluting with 25%
methanol/0.2%isopropylamine/CO2 to afford of
3-(1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclobutyl-ethyl)-pyrrolidine
(D1E1) (21 mg, 40%, >99%ee) and
3-(1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclobutyl-ethyl)-pyrrolidine
(D1E2) (20 mg, 38%, >99 ee).
[0170] The L-tartarte formation of
3-(1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclobutyl-ethyl)-pyrrolidine
(D1E2) is essentially performed as in EXAMPLE 1 to afford the title
compound. MS (m/z)=295.2 (M+1)
EXAMPLE 34
(3S)-3-(1-(6-Methoxy-2-methyl-3-pyridyloxy)-butyl)-pyrrolidine,
L-tartrate (S-2).
##STR00074##
[0171] De-Salting.
[0172] Dissolve the L-tartrate salt of
(3S)-3-(1-(6-chloro-2-methyl-3-pyridyloxy)-butyl)-pyrrolidine (S-2)
(1.00 g, 2.39 mmol) in methanol and pour the solution onto a SCX
column. Rinse the column with methanol and then elute the free
amine with 2M NH.sub.3 in methanol. Evaporate the solvent and dry
the amine under vacuum to yield 0.65 g (99%) of
(3S)-3-(1-(6-chloro-2-methyl-3-pyridyloxy)-butyl)-pyrrolidine (S-2)
which was used in the next step without further purification.
Chloride to Methoxy Displacement
[0173] Add
(3S)-3-(1-(6-chloro-2-methyl-3-pyridyloxy)-butyl)-pyrrolidine (S-2)
(0.65 g, 2.44 mmol), DMSO (9.75 mL), methanol (0.493 mL, 12.18
mmol), and sodium hydride (0.390 g, 9.75 mmol) to a reaction vial.
Evacuate the vial and purge with nitrogen. Heat the mixture at
100.degree. C. over night. Pour the reaction mixture onto an SCX
column and rinse with methanol. Attach the SCX column on top of a
silica gel column and elute with 5-30% of NH3OH/ethanol (1:9) in
chloroform to obtain 0.420 g (65%) of
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-butyl)-pyrrolidine
[0174] The L-tartarte formation of
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-butyl)-pyrrolidine
(S-2) is essentially performed as in EXAMPLE 1 to afford the title
compound. MS (m/z)=265 [M+1]
EXAMPLE 35
(3S)-3-[1-Cyclobutyl-1-(6-methoxy-2-methyl-3-pyridyloxy)-methyl]-pyrrolidi-
ne (S-1), L-tartrate
##STR00075##
[0176] The title compound may be prepared from
(3S)-3-[1-cyclobutyl-1-(6-chloro-2-methyl-3-pyridyloxy)-methyl]-pyrrolidi-
ne (S-1), L-tartrate essentially as described in EXAMPLE 34. MS
(m/z)=277 [M+1]
EXAMPLE 36
(3S)-3-[1-(6-Methoxy-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne, L-tartrate (S-1)
##STR00076##
[0177] Deprotection
[0178] Mix
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-
-pyrrolidine-1-carboxylic acid tert-butyl ester (S-1) (0.50 g, 1.31
mmol), methoxybenzene (6.6 mL) and dichloromethane (6.6 mL) in a
reaction vial. Evacuate the vial and purge with nitrogen. Add
trifluoroacetic acid (1.51 g, 1.0 mL, 13.2 mmol) and stir the
mixture at room temperature for 1 h. Load the mixture directly onto
a pre-packed SCX column and rinse with CH.sub.2Cl.sub.2 followed by
CH.sub.3OH. Elute with 2M NH.sub.3 in methanol and concentrate
under reduced pressure to give 0.353 g (96%) of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne (S-1). MS (m/z)=281.2 [M+1].
Chloride to Methoxy Displacement
[0179] Add
(3S)-3-(1-(6-chloro-2-methyl-3-pyridyloxy)-cyclopropyl-ethyl)-p-
yrrolidine (S-1) (0.35 g, 1.25 mmol), DMSO (4.99 mL), methanol
(0.404 mL, 9.97 mmol), and sodium hydride (0.349 g, 8.73 mmol) to a
reaction vial. Evacuate the vial and purge with nitrogen. Heat the
mixture at 110.degree. C. for 4 h. Dissolve the reaction in a pH 7
buffer and neutralize with 5N HCl. Pour the mixture onto an SCX
column and rinse with methanol. Attach the SCX column on top of a
silica gel column and elute with 5-35% of NH.sub.4OH/ethanol (1:9)
in chloroform to obtain 0.209 g (61%) of
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl)-pyrrolid-
ine (S-1). MS (m/z)=277 [M+1].
[0180] The L-tartarte formation of
(3S)-3-(1-(6-methoxy-2-methyl-3-pyridyloxy)-cyclopropyl-ethyl)-pyrrolidin-
e (S-1) is essentially performed as in EXAMPLE 1 to afford the
title compound. MS (m/z)=277 [M+1]
EXAMPLE 37
(3S)-3-[1-(6-Chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidin-
e, L-tartrate (S-1)
##STR00077##
[0181] Preparation of Weinreb Amide
##STR00078##
[0183] Add a solution of
(S)-N-tert-butoxycarbonylpyrrolidine-3-carboxylic acid (40 g, 186
mmol) in THF (240 mL) dropwise to a stirred solution of
1,1'-carbonyldiimidazole (31.4 g, 190 mmol) in THF (160 mL) and
stir at room temperature under nitrogen for 2.5 hours. Add
N,O-di-methylhydroxylamine hydrochloride (18.8 g, 190 mmol) and
stir at room temperature over night. Quench the reaction with
water. Separate the phases and extract the water phase with
t-butylmethylether (2.times.). Combine the organics and wash with
10% aqueous H.sub.3PO.sub.4, 20% aqueous KHCO.sub.3, water and
brine. Concentrate to afford 37.1 g (77%) of the title compound. MS
(m/z)=203.1 [M-55]
Addition of Grignard to Weinreb Amide and Reduction of the Ketone
to the Alcohol
##STR00079##
[0185] Add slowly and dropwise a solution of allylmagnesium bromide
(2.0 M in THF, 100.3 mL, 200.5 mmol) to a stirred solution of
(S)-3-(methoxy(methyl)carbamoyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (37.0 g, 143.2 mmol) in THF (296 mL) kept under
nitrogen at 0.degree. C. Allow the reaction to warm to room
temperature and continue to stir for 48 hours. Add the mixture over
a cold solution (0-5.degree. C.) of sodium borohydride (5.42 g, 143
mmol) and tertabutylammonium bromide (0.74 g, 2.39 mmol) in water
(74 mL) and stir for 1 hour. Separate the phases and extract the
water phase with t-butylmethylether (2.times.). Combine the organic
phases and wash with water and brine. Concentrate and purify the
crude residue by silica gel column chromatography eluting with
t-butylmethylether/hexanes (3/7 to 7/3) to obtain
(3S)-3-(1-hydroxy-but-3-enyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester (S-mix) (29 g, 85%). MS (m/z)=186.1 [M-55].
(3S)-3-(2-cyclopropyl-1-hydroxyethyl)pyrrolidine-1-carboxylic acid
tert butyl ester (S-mix)
##STR00080##
[0187] Add palladium (II) acetate (2.31 g; 0.298 mmol) to a stirred
solution of (3S)-3-(1-hydroxy-but-3-enyl)-pyrrolidine-1-carboxylic
acid tert-butyl ester (S-mix) (14.4 g, 59.7 mmol) in
dichloromethane (43.2 mL). Add slowly a freshly prepared solution
of diazomethane (100 mL, about 50 mmol in diethyl ether) under
nitrogen at -30 to -40.degree. C. (Caution: vigorous N.sub.2 gas
evolution). Evaporate the solvent and dissolve the crude in
dichloromethane (43.2 mL). Add palladium (II) acetate (2.31 g,
0.298 mmol) followed by a freshly prepared solution of diazomethane
(100 mL, about 50 mmol in diethyl ether) to the mixture kept under
nitrogen at -30 to -40.degree. C. (Caution: vigorous N.sub.2 gas
evolution). Evaporate the solvent and dissolve the crude in
dichloromethane (43.2 mL). Add palladium (II) acetate (2.31 g,
0.298 mmol) followed by a freshly prepared solution of diazomethane
(50 mL, about 25 mmol in diethyl ether) to the mixture kept under
nitrogen at -30 to -40.degree. C. (Caution: vigorous N.sub.2 gas
evolution). Evaporate the solvent, add hexanes (140 mL) to the
crude residue and stir the suspension over night at room
temperature. Filter the suspension over a pad of celite.RTM. and
concentrate to obtain a quantitative yield
(3S)-3-(2-cyclopropyl-1-hydroxyethyl)pyrrolidine-1-carboxylic acid
tert butyl ester (S-mix). MS (m/z)=200.1 [M-55].
(3S)-3-[1-(6-Chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidin-
e-1-carboxylic acid tert-butyl ester (S-1) and (S-2)
##STR00081##
[0189] Add sodium hydride (60%, 6.20 g, 155.1 mmol) slowly to a
mixture of
(3S)-3-(2-cyclopropyl-1-hydroxy-ethyl)-pyrrolidine-1-carboxylic
acid tert-butyl ester (S-mix) (19.8 g, 77.5 mmol),
6-chloro-3fluoro-2-methyl-pyridine (16.9 g, 116.3 mmol) and
dimethylacetamide (59.4 mL) kept under an atmosphere of nitrogen at
room temperature. Heat to 40.degree. C. and stir for 3.5 hours.
Cool the mixture and add methanol. Pour the mixture over 10%
aqueous H.sub.3PO.sub.4 (100 mL)and t-butylmethylether (100 mL).
Separate the phases and extract the water phase with
t-butylmethylether (2.times.). Combine the organic phases and wash
with water and brine. Evaporate the solvent to obtain a crude
residue. Chromatograph the crude residue on silica gel eluting with
t-butylmethylether/hexanes (2:8 to 4:6) to obtain a crude residue
which was mixed with crude residue from another batch (based on 2 g
of the alcohol). The mixture of diastereomers was separated by
silica gel chromatography eluting with 25% of t-butylmethylether in
hexanes to obtain
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne-1-carboxylic acid tert-butyl ester, isomer 1, (S-1) (15.0 g,
51%) as the first eluting isomer, MS (m/z)=325.0 (M-55) and
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne-1-carboxylic acid tert-butyl ester, isomer 2, (S-2) (12.0 mg,
41%) as the second eluting isomer. MS (m/z)=325.0 (M-55).
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidin-
e, (S-1)
##STR00082##
[0191] Add HCl (4M in 1,4-dioxane, 52.7 mL, 627 mmol) to a solution
of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne-1-carboxylic acid tert-butyl ester (S-1) (13.4 g, 35.2 mmol) in
dichloromethane (40.2 mL). Stir under nitrogen at room temperature
for 1 h. Evaporate the solvent and dissolve the residue in a
mixture of t-butylmethylether (40 mL) and water (40 mL). Separate
the phases, wash the aqueous phase with t-butylmethylether
(2.times.). Adjust the pH of the aqueous phase to 9 by the addition
of 10% aqueous K.sub.2CO.sub.3, extract with t-butylmethylether
(3.times.). Wash the combined organic phases with water and brine.
Evaporate the volatiles to obtain
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne (S-1) (9.6 g, 97%). MS (m/z)=281.2 [M+1]
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidin-
e, L-tartrate (S-1)
##STR00083##
[0193] Add L-tartaric acid (5.1 g, 33.9 mmol) to a solution of
(3S)-3-[1-(6-chloro-2-methyl-3-pyridyloxy)-2-cyclopropyl-ethyl]-pyrrolidi-
ne (S-1) (9.7 g, 34.5 mmol) in methanol (48.5 mL). Stir the mixture
at room temperature for 15 minutes under nitrogen. Evaporate the
volatiles, dissolve the residue in water (100 mL) and extract with
t-butylmethylether (2.times.). Concentrate on the rotary evaporator
the aqueous phase to a final volume of 50 mL while keeping the bath
at 25.degree. C. Lyophilize the residue to obtain 14.0 g, (95%) of
the title compound. MS (m/z): 281.0 [M+1]
Assignment of Absolute Configuration of
3(S)-(1'-Hydroxy-3'-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester Isomers 1 and 2
[0194] There are two stereogenic carbons in
3(S)-(1'-hydroxy-3'-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester which correspond to carbons 5 and 7 (C5 and C7) as
illustrated in FIG. 1.
##STR00084##
[0195] Because the configuration of C7 is known from the starting
(S)--N-(tert-butoxycarbonyl)-pyrrolidine-3-carboxylic acid, the
determination of relative configuration would lead to the
assignment of the absolute configuration at C5. The relative
configuration of flexible molecules can be accomplished if
proton-carbon couplings are considered through the J-based
configuration method described by Matsumori et al., J. Org. Chem.
64, 866 (1999). This approach involves the measurement of H--H and
H--C couplings across a certain C--C bond and their conversion to
dihedral angles via the Karplus-Altona relationship. The H--C
couplings also follow a Karplus relationship, and small values,
ranging from 1 to 3 Hz, are indicators of gauche orientations, and
large values, ranging from 6 to 8 Hz, indicate anti
arrangements.
[0196] The relevant H5-C11 proton-carbon coupling constant are
measured using the satellite-selective 1D-TOCSY experiment
described by P. Vidal, et al., J. Org. Chem., 72, 3166-3170 (2007).
The 1D-TOCSY experiments in which the offset of the selective pulse
are set on the low-frequency .sup.13C satellite of H11 are
acquired. The resulting spectrum is compared with the conventional
1D-TOCSY experiment in which the H11 signal of the major 12C
isotopomer is excited, or alternatively with the 1H spectrum. The
three-bond H,C couplings between C11 and H5 is determined from the
displacement of the relayed H5 signal in the satellite-selective
TOCSY spectra relative to its position in the 1H spectrum, the
coupling constant being twice the displacement. The coupling
constant between C8 and H5 is not measured due to signal
overlapping. The proton-proton and proton-carbon coupling constants
across the C7-C5 bond are measured for each of
3(S)-(1-hydroxy-3-methyl-butyl)-pyrrolidine-1-carboxylic acid
tert-butyl ester Isomer 1 and Isomer 2 prepared essentially as
described in Preparation 4 and their values are in the following
table.
TABLE-US-00009 Compound H--H or H--C Pair .sup.3J (Hz) Isomer 1
H5--H7 7.0 Isomer 1 H5--C11 4.2 Isomer 2 H5--H7 7.0 Isomer 2
H5--C11 1.8
[0197] The small H5-C11 coupling constant in Isomer 2 indicates
that H5 and C11 are gauche to each other in both populated
conformers, which is consistent with the 3(S)-1'(S) isomer.
In vitro Transporter Affinity Assay
[0198] Human serotonin transporter (SERT), norepinephrine
transporter (NET), or dopamine transporter (DAT) are cloned into a
pcDNA3 vector and stably transfected into HEK293 cells. Membrane
stocks are prepared following standard protocols, and K.sub.d
values are calculated using saturation binding or homologous
competition binding methods for each batch of membranes (Bylund and
Toews, Am. J. Phys. (Lung Cell. Mold Physiol 9), 265, 421-429
(1993). All binding assays are conducted in 96-well plates using a
method developed by converting a filtration radioligand binding
assay to a scintillation proximity assay (SPA) format (Carpenter,
et al., Methods in Molecular Biology, 190, 21-49 (2002)). Briefly,
SERT membranes are used at a concentration of 10 .mu.g/well in
assay buffer containing 50 mM Tris, 150 mM NaCl, and 5 mM KCl (pH
7.4) in the presence of .sup.3H-citalopram. Fluoxetine (100 .mu.M)
is used to determine non-specific binding, and venlafaxine is used
as a positive control. NET membranes are used at a concentration of
8 .mu.g/well in assay buffer containing 50 mM Tris, 300 mM NaCl,
and 5 mM KCl (pH 7.4). .sup.3H-Nisoxetine is used as the tracer,
100 .mu.M desipramine serves as a measure of non-specific binding,
and nisoxetine is used as the positive control. For DAT binding
assays, the assay buffer is the same as for SERT, membranes are
used at 20 .mu.g/well, 100 .mu.M nomifensine is used to determine
non-specific binding, .sup.3H-WIN 35428 (Perkin Elmer) serves as
the radiotracer, and nomifensine is used as the positive control.
In all cases, 0.5 mg/well of wheat-germ agglutinin scintillation
proximity assay beads (WGA-SPA, GE Health Sciences) are used to
capture the membranes, and plates are incubated for 3 hours at room
temperature. Radioactivity is measured and K.sub.i values
calculated using a four-parameter logistic curve fitting program
(ActivityBase v5.3.1.22).
[0199] Exemplified compounds are tested essentially as described
above and are found to have high affinity for the hSERT and hNET
receptors, but much lower affinity for the hDAT receptor in vitro.
K.sub.i for SERT and NET are found to be less than 20.1 nM and 23.4
nM, respectively, while the K.sub.i for DAT is found to be greater
than 255 nM. The compound of EXAMPLE 19 is tested essentially as
described above and is found to have affinities as shown in the
table below.
TABLE-US-00010 RECEPTOR K.sub.i (nM) hSERT 0.199 .+-. 0.02 (n = 6)
hNET 1.08 .+-. 0.32 (n = 6) hDAT 461 .+-. 72 (n = 6) (mean .+-. std
error)
In vitro Inhibitor Activity Assay:
[0200] Human serotonin (SERT) or norepinephrine (NET) transporters
are cloned into a pcDNA3 vector and stably transfected into HEK293
cells. Both assays are modified from methods described by Eshleman
et al., J. Pharmacol. Exptl Ther., 289, 877-885 (1999)) and Wall et
al., Mol. Pharmacol., 47, 544-550 (1995). Cells are grown on
poly-D-lysine coated flasks or 96-well plates in D-MEM/F-12 3:1 (3
part of Dulbecco's Modified Eagle Medium in 1 part of Nutrient Mix
F-12 medium) containing 5% fetal bovine serum, 250 .mu.g/mL
geneticin, and 20 mM Hepes. Cells are plated at 40,000 cells per
well in 200 .mu.L of medium and incubated for 18-24 hours at
37.degree. C. prior to the assay. The assay uptake buffer consists
of Krebs-Ringer bicarbonate stock supplemented with 1.26% sodium
bicarbonate, 20 mM HEPES, and 100 .mu.M each of pargyline and
ascorbic acid. Following a 30 minute pre-incubation with the
compound or indatraline (as a positive control), .sup.3H-serotonin
or .sup.3H-norepinephrine is added for 1 min. and 50 sec. The
.sup.3H-substrate is then removed, and the cells washed 4.times.
with 100 .mu.L of cold uptake buffer using multimek. Triton X-100
(1%) is added to lyse the cells and, after mixing, all the contents
are transferred to a white-bottom plate. Microscint.TM. 40 is added
to each well and the radioactivity is quantitated for 1 min. per
well. Results are analyzed as IC.sub.50 values using a
four-parameter logistic curve fitting program (ActivityBase
v5.3.1.22).
[0201] Exemplified compounds are tested essentially as described
above and are found to be inhibitors of serotonin and
norepinephrine reuptake, having IC.sub.50 of SERT and NET of less
than 227 nM and 44.6 nM, respectively. The compound of EXAMPLE 19
is tested essentially as described above and is found to be an
inhibitor of serotonin and norepinephrine reuptake in vitro, having
IC.sub.50's as shown in the table below.
TABLE-US-00011 RECEPTOR IC.sub.50 (nM) hSERT 2.15 .+-. 0.70 (n = 4)
hNET 7.34 .+-. 1.48 (n = 4) (mean .+-. std error)
In vivo Transporter Occupancy Assay:
[0202] Male Sprague-Dawley rats weighing 240-280 gm in groups of
three are used to determine serotonin transporter occupancy.
Animals are fasted at least 12 hr. before the start of each
experiment. Animals are orally administered vehicle or 0.10, 0.33,
1.00, 3.33 or 10.00 mg/kg doses of test compound in 4% Glucose in
25 mM Phosphate buffer, (pH=3.0) containing 0.1, 0.33, 1, 3.33, or
10% CAPTISOL.TM. (concentration of CAPTISOL.TM. (%)=dose of test
compound (mg/kg)). After 2 hr., animals are intravenously
administered N,N-dimethyl-2-(2-amino-4-cyanophenylthio)-benzylamine
(10 .mu.g/kg) in saline in the lateral tail vein. After an
additional 40 min., rats are sacrificed via cervical dislocation,
and a portion of the frontal cortex is removed and placed on dry
ice. An additional control group of three rats is dosed with
paroxetine maleate at 12 mg/kg, i.v., followed by
N,N-dimethyl-2-(2-amino-4-cyanophenylthio)-benzylamine (10
.mu.g/kg) 1 hr. later.
[0203] Tissues are allowed to thaw and then four volumes (w/v) of
acetonitrile containing 0.1% formic acid is added. Samples are
homogenized using an ultrasonic dismembrator probe and centrifuged
for 16 min. at 14,000.times.g. One volume of the supernatant is
added to 3 volumes of water in an autosampler vial and vortexed.
Separation is achieved with a Zorbax C18 HPLC column and a mobile
phase gradient of from 20% to 90% acetonitrile/water, each with
0.1% formic acid. The total HPLC run time is 3.5 min with an
additional 2.0 min re-equilibration time. An API4000 triple
quadrupole mass spectrometer (Applied Biosystems, Foster City,
Calif., USA) operating in MRM mode is used for detection. The ion
transition monitored is 284.1/239.1 m/z for
N,N-dimethyl-2-(2-amino-4-cyanophenylthio)-benzylamine.
[0204] The level of
N,N-dimethyl-2-(2-amino-4-cyanophenylthio)-benzylamine (tracer) in
the cortex of vehicle-pretreated animals represents the sum of
nonspecific and specific binding and is assigned the value of 0%
occupancy (all receptors available to the tracer). The lower level
of tracer in animals pretreated with the very high intravenous dose
of paroxetine maleate, the positive control group, represents the
nonspecific binding and is assigned the value of 100% occupancy (no
receptors available to the tracer). Levels of tracer in the cortex
following oral administration of test compound are interpolated
linearly between these two extremes in order to determine the
percent serotonin transporter occupancy. Data are expressed as
means.+-.SEM (n=3/group) calculated using Prism version 3.0
(GraphPad Software Inc., San Diego, Calif., USA). The ED.sub.80
values are obtained by fitting the data to a sigmoidal curve using
nonlinear regression.
[0205] The compound of EXAMPLE 19 is tested essentially as
described above and is found to have an absolute ED.sub.80 of 7.1
mg/kg, based on the below dose response data for 1 hr. post dosing,
thus confirming occupancy of serotonin receptors in vivo.
TABLE-US-00012 Dose (mg/kg p.o.) % Occupancy S.E.M. 30 105.6 1.8 10
94.0 3.6 3 43.3 5.8 1 25.0 4.2 0.3 5.9 3.9 ED.sub.80 7.1 mg/kg
Alpha MMT: Monoamine Depletion Inhibition Assay:
[0206] Neurotransmitter transporter inhibitors can prevent the
depletion of brain monoamines when the depleting agent requires
active uptake into neurons via a transporter.
DL-Para-chloroamphetamine (PCA) is transported into serotonergic
neurons via the neuronal transporter and produces a long-lasting
depletion of rat brain serotonin (5-HT) concentrations.
Alpha-methyl-m-tyrosine (.alpha.-MMT) is a noradrenergic depleting
agent that is .beta.-hydroxylated to metaraminol in vivo and
actively transported into norepinephrine (NE) neurons via the
neuronal transporter producing a decrease in NE levels in rat
brain. The depletion of rat brain 5-HT levels by PCA and rat
cortical NE concentrations by .alpha.-MMT is blocked by agents with
5-HT and NE reuptake inhibitor activity. Compounds of the present
invention may be assayed for their activity to prevent the
depletion of rat brain 5-HT concentrations by PCA and the depletion
of rat cortical NE concentrations by a-MMT in fed and fasted rats
in vivo using the following methods.
[0207] Male Sprague Dawley rats weighing 160-180 grams are fasted
overnight or allowed food ad libidum. Animals are gavaged with
vehicle (sterile H.sub.2O) or test compound 2 hr. prior to
administration of 10 mg/kg PCA hydrochloride (ip) or 6.25 mg/kg
.alpha.-MMT (sc). All compounds are administered at 1 mL/kg.
Animals are sacrificed 2 hr. after PCA or .alpha.-MMT
administration. Tissues are dissected, frozen on dry ice and stored
at -70.degree. prior to analysis. For animals administered PCA,
whole brain serotonin (5-HT) concentrations are measured using
high-pressure liquid chromatography with electrochemical detection
as described by Fuller and Perry in J. Pharmacol. Exp. Ther., 248,
50-56 (1989). For animals administered a-MMT, cortical
norepinephrine concentrations are measured by HPLC-EC after alumina
absorption as described by Bymaster, et al.,
Neuropsychopharmacology, 27(5), 699-711 (2002). The data are
collected using an EZChrom.TM. chromatography data system
(Scientific Software, San Ramon, Calif.) which calculates peak
heights and sample concentrations. Analysis of variance, followed
by Tukey's Honestly Significant Difference test post hoc,
identifies significant differences between treatment groups
(P.ltoreq.0.05). Doses that antagonized the PCA- or
.alpha.-MMT-induced depletion of monoamines by 50 percent,
(ED.sub.50's) are calculated using a best-fit linear regression
analysis.
[0208] The compound of EXAMPLE 19 is tested essentially as
described above and is found to antagonize .alpha.-MMT induced
depletion of norepinephrine in rat cortex with an ED.sub.80 of 9.5
mg/kg as based on the dose responses below, thus confirming in vivo
efficacy at inhibiting norepinephrine transporter function.
TABLE-US-00013 Dose (mg/kg p.o.) % Inhibition S.E.M. 30 115.3 14.6
10 79.0 9.3 3 21.0 5.5 1 5.6 3.9 0.3 7.0 10.4 ED.sub.80 9.5
mg/kg
Manual Formalin Test
[0209] The manual formalin test is performed in custom-made
Plexiglas boxes approx. 25 cm.times.25 cm.times.20 cm in size. A
mirror placed at the back of the cage allows the unhindered
observation of the formalin injected paw. Rats (Charles River (CRL)
Sprague Dawley (SD)) are placed individually in the cubicles at
least 30 min. prior to the experiment. All testing is conducted
between 08:00 and 14:00 h and the testing room temperature is
maintained at 21-23.degree. C. Peripherally administered test
compounds are dosed at varying times before the formalin challenge.
Formalin (50 .mu.L of a 5% solution in saline) is injected
subcutaneously into the dorsal lateral surface of the right hind
paw with a 27 gauge needle. Observation starts immediately after
the formalin injection. Formalin induced pain is quantified by
recording the number of seconds each licking event lasts in 5 min.
intervals. The pain scoring is measured for 50 min. after the
formalin injection. Two phases of pain behavior are observed as
previously described (Wheeler-Aceto, H., Porreca, F. and Cowan, A.,
The rat paw formalin test: comparison of noxious agents, Pain 40
(1990) 229-238.). The early phase starts immediately after the
formalin injection and lasts approximately 5 min., followed by the
late phase that starts between minutes 10-15 with a maximum
response typically observed around 25-35 min. after the formalin
injection. After the 50 min. observation period, animals are
sacrificed with CO.sub.2.
[0210] Of the different scoring parameters reported for the
formalin test, the total time spent licking and biting the injected
paw is considered to be most relevant. (Abbott et al., The formalin
test: scoring properties of the first and second phases of the pain
response in rats, Pain 60 (1995) 91-102; Coderre et al., The
formalin test: a validation of the weighted-scores method of the
behavioral pain rating, Pain 54 (1993) 43-50).) The early phase
score is the sum of time spent licking (seconds) from time 0 to 5
min. The late phase score is obtained by adding the total number of
seconds spent licking from minute 16 to min. 40 of the observation
period. Data are presented as means with standard errors of means
(.+-.SEM). Data is evaluated by one-way analysis of variance
(ANOVA) and the appropriate contrasts analyzed by Dunnett "t' test
for two sided comparisons. Differences are considered to be
significant if the P-value is less than 0.05. (Abbott, supra.;
Coderre, supra.; and Wheeler-Aceto, supra.)
[0211] The compound of EXAMPLE 19 is tested essentially as
described above and is found to significantly reduce pain behavior
with an ED.sub.50 of 13.4 mg/kg deriving from the following dose
responses:
TABLE-US-00014 % reduction in total time Dose (mg/kg p.o.) licking
S.E.M. 30 78.4 5.6% 10 38.0 7.8% 3 14.4 13.0% 1 4.5 8.3% ED.sub.50
13.4 mg/kg
[0212] While it is possible to administer compounds employed in the
methods of this invention directly without any formulation, the
compounds are usually administered in the form of pharmaceutical
compositions comprising at least one compound of Formula I, or a
pharmaceutically acceptable salt thereof, as an active ingredient
and at least one pharmaceutically acceptable carrier, diluent
and/or excipient. These compositions can be administered by a
variety of routes including oral, intranasal, transdermal,
subcutaneous, intravenous, intramuscular, and pulmonary. Such
pharmaceutical compositions and processes for preparing them are
well known in the art. See, e.g., Remington: The Science and
Practice of Pharmacy (University of the Sciences in Philadelphia,
ed., 21.sup.st ed., Lippincott Williams & Wilkins Co.,
2005).
[0213] The compositions are preferably formulated in a unit dosage
form, each dosage containing from about 0.1 to about 500 mg, more
usually about 1.0 to about 200 mg, as for example between about 1
and 20 mg of the active ingredient. The term "unit dosage form"
refers to physically discrete units suitable as unitary dosages for
human subjects and other mammals, each unit containing a
predetermined quantity of active material calculated to produce the
desired therapeutic effect, in association with at least one
suitable pharmaceutically acceptable carrier, diluent and/or
excipient.
[0214] The compounds of Formula I are generally effective over a
wide dosage range. For example, dosages per day normally fall
within the range of about 0.001 to about 30 mg/kg, more usually
from about 0.01 to 3.0 mg/kg, and as for example between 0.01 and
0.3 mg/kg of body weight. In some instances dosage levels below the
lower limit of the aforesaid range may be more than adequate, while
in other cases still larger doses may be employed without causing
any harmful side effect, and therefore the above dosage range is
not intended to limit the scope of the invention in any way. It
will be understood that the amount of the compound actually
administered will be determined by a physician, in the light of the
relevant circumstances, including the condition to be treated, the
chosen route of administration, the actual compound or compounds
administered, the age, weight, and response of the individual
patient, and the severity of the patient's symptoms.
* * * * *
References